Document:

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                                                                   EXHIBIT 10.39

                        FOUNDER STOCK PURCHASE AGREEMENT

     This Founder Stock Purchase Agreement is dated as of the tenth day of June
1998 (the "Effective Date") by and between MachOne Communications, Inc., a
California corporation (the "Company"), and Matthew J. Stepovich ("Founder").

                                   WITNESSETH:

     WHEREAS, Founder is a founder and a key employee of the Company.

     WHEREAS, Founder has purchased from the Company 72,000 shares of the
Company's Common Stock (the "Original Shares") pursuant to that certain Founder
Stock Purchase Agreement, by and between Company and Founder, dated as of
December 23, 1997 (the "Initial Purchase Agreement").

     WHEREAS, the Company desires to issue and the Founder desires to acquire
stock of the Company as herein described, on the terms and conditions
hereinafter set forth.

     NOW, THEREFORE, IT IS AGREED between the parties as follows:

     1. Number of Shares and Price Per Share. The Founder hereby agrees to
purchase from the Company and the Company agrees to sell to the Founder one
hundred seventy-eight thousand (178,000) shares of the Company's Common Stock
(the "Stock") with a fair market value of $1,780.00 (or $0.01 per share). The
consideration for the Stock (the "Purchase Price") will be paid by Purchaser in
cash, by check, or promissory note concurrent with the execution of this
Agreement against the Company's delivery of a stock certificate evidencing the
Stock.

     2. Unvested Share Repurchase Option. The Company shall have the option (the
"Unvested Share Repurchase Option") to reacquire any shares purchased pursuant
to this Agreement which have not vested in the Founder pursuant to subsection
2(a) (the "Unvested Shares") under the terms set forth in this Section 2. The
parties hereto acknowledge and agree that

          (a) Vesting of Shares. Founder shall purchase the Stock effective upon
the date first written above, but the "Initial Vesting Date" for determination
of vesting of the Stock shall be December 3, 1997. The shares of Stock purchased
by the Founder will vest (the "Vested Shares") on and after the Initial Vesting
Date in accordance with the following formula:

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<TABLE>
<CAPTION>
Date                                    Number of Shares Vested
----                                    -----------------------
<S>                                     <C>
On the Initial Vesting Date             25,958 shares of Stock will
                                        vest (14.5832%)

For each full month of the Company's    An additional 2.0833% of the
continuous employment of Founder        Stock will vest (3,708 shares)
following the Initial Vesting Date      for each full month of service.
</TABLE>

     Provided that the aggregate number of shares of Stock constituting Vested
Shares may not exceed 178,000 shares (as adjusted for stock splits and the
like). In the event a fraction of a share is vested, the number of vested shares
shall be rounded to the nearest whole number. The parties acknowledge that
nothing in this Agreement shall revise or alter the vesting provisions for the
Original shares as set forth in the Initial Purchase Agreement.

          (b) Exercise of Unvested Share Repurchase Option. If the Founder's
employment with the Company is terminated for any reason, with or without cause,
voluntarily or involuntarily, including termination due to death or disability
(as defined below), or if the Founder or the Founder's legal representative
attempts to dispose of any Unvested Shares other than as allowed in this
Agreement, the Company may exercise the Unvested Share Repurchase Option by
written notice to the Escrow Agent (as defined in Section 8) and to the Founder
or the Founder's legal representative within 60 days after such termination or
after the Company has received notice of the attempted disposition.

          (c) Payment for Shares and Return of Shares. Payment by the Company to
the Escrow Agent on behalf of the Founder or the Founder's legal representative
shall be made in cash within 60 days after the date of the mailing of the
written notice of exercise of the Unvested Share Repurchase Option. For purposes
of the foregoing, cancellation of any promissory note of the Founder to the
Company shall be treated as payment to the Founder in cash to the extent of the
unpaid principal and any accrued interest canceled. The purchase price per share
being purchased by the Company pursuant to the Unvested Share Repurchase Option
shall be $0.001 per share, adjusted appropriately to reflect any stock split,
stock dividend, recapitalization, etc. Within 30 days after payment by the
Company, the Escrow Agent shall give the shares which the Company has purchased
to the Company and shall give the payment received from the Company to the
Founder.

          (d) Early Termination of Unvested Share Repurchase Option. The other
provisions of Section 2 notwithstanding, upon any Transfer of Control (as
defined below), the Unvested Share Repurchase Option shall terminate as of a
date prior to the Transfer of Control, as the Board so determines pursuant to
the definition below, or if no such determination is made, two days prior to the
closing of the transaction involving the Transfer of Control. Any such
termination that was permissible solely by reason of this subsection 2(d) shall
be conditioned upon the consummation of the Transfer of Control. For purposes of
this subsection 2(d), a Transfer of Control shall be deemed to have occurred
upon any of the following events: (i) the direct or indirect sale or exchange by
the shareholders of the Company of all or substantially all of the stock of the
Company where the shareholders of the Company before such sale or

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exchange do not retain, directly or indirectly, at least a majority of the
beneficial interest the voting stock of the Company; (ii) a merger in which the
shareholders of the Company before the merger do not retain, directly or
indirectly, at least a majority of the beneficial Interest in the voting stock
of the Company; or (iii) the sale, exchange, or transfer of all or substantially
all of the Company's assets (other than a sale, exchange, or transfer to one or
more corporations where the shareholders of the Company before such sale,
exchange, or transfer retain, directly or indirectly, at least a majority of the
beneficial interest in the voting stock of the corporation(s) to which the
assets were transferred).

          For the purposes of early termination of the unvested share repurchase
option, a Transfer of Control shall be deemed to have occurred only if one of
the events described in the paragraph above has occurred and, within one year of
such event: (i) there is a decrease in Founder's base salary, benefits and/or
bonus compensation; (ii); (iii) there is a material breach by Company (or its
successor or assign) of this Agreement or of Founder's Employment Agreement with
the Company; (iv) the Company fails to obtain the assumption of this Agreement
and the Employment Agreement by MachOne's successor or assign.

          (e) Transfers Not Subject to the Unvested Share Repurchase Option. The
Unvested Share Repurchase Option shall not apply to a transfer of shares of the
Stock to the Founder's ancestors, descendants or spouse or to a trustee for
their benefit or the benefit of the Founder, provided that such transferee shall
agree in writing (in a form satisfactory to the Company) to take the shares of
the Stock subject to all the terms and conditions of this Section 2.

          (f) Assignment of Unvested Share Repurchase Option. The Company may
assign the Unvested Share Repurchase Option to one or more persons, who shall
have the right to exercise the Unvested Share Repurchase Option in his or her
own name for his or her own account.

     3. Right of First Refusal. Before any shares of the Stock registered in the
name of Founder may be sold or transferred (including transfer by operation of
law), such shares shall first be offered to the Company, which will have the
right to purchase all or any part of such shares proposed to be transferred
("Right of First Refusal"), in the following manner:

          (a) Transfer Notice. The Founder or his or her legal representative
shall first give written notice (the "Transfer Notice") of any proposed transfer
to the Company. The Transfer Notice shall name the proposed transferee, state
the number of shares of Stock to be transferred, the price per share and all
other terms of the offer. The Transfer Notice shall be signed by the Founder or
his or her representative and the prospective transferee and must constitute a
binding agreement for the transfer of the Stock subject only to the Right of
First Refusal.

          (b) Bona Fide Determination. Within 30 days of delivery of the
Transfer Notice, the Company's Board of Directors shall determine the bona fide
nature of the proposed transfer and give the Founder written notice of its
determination. If the proposed transfer is deemed to be bona fide, the remaining
subsections of this section shall apply to the sale. If the

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proposed transfer is deemed not to be bona fide, the Founder will be responsible
for providing additional information to the Board to show the bona fide nature
of the proposed transfer and no Stock will be transferred on the books of the
Company until the Board has approved the proposed transfer as bona fide.

          (c) Failure to Exercise; Exercise. If the Company elects not to or
fails to exercise in full the Right of First Refusal within 30 days from the
later of the date the Transfer Notice is delivered to the Company or 30 days
after the date the transfer is determined to be bona fide (if the Founder is
required to provide additional information as provided in Section 3(b)), the
Founder may, by the later of 60 days after the delivery of the Transfer Notice
to the Company or 30 days after the date the transfer is determined to be bona
fide (if the Founder is required to provide additional information as provided
in Section 3(b)), conclude a transfer of the shares of Stock subject to the
Transfer Notice which have not been purchased by the Company pursuant to
exercise of the Right of First Refusal on the terms and conditions described in
the Transfer Notice. Any proposed transfer on terms and conditions different
from those described in the Transfer Notice, as well as any subsequent proposed
transfer by the Founder, shall again be subject to the Right of First Refusal
and shall require compliance by the Founder with the procedure described in this
Section 3. If the Company exercises the Right of First Refusal, the parties
shall consummate the sale of shares of Stock on the terms set forth in the
Transfer Notice by the later of 60 days after the delivery of the Transfer
Notice to the Company or 30 days after the date the transfer is determined to be
bona fide (if the Purchaser is required to provide additional information as
provided in Section 3(b)); provided, however, in the event the Transfer Notice
provides for the payment for the shares of Stock other than in cash, the Company
shall have the option of paying for the shares of Stock by the discounted cash
equivalent of the consideration described in the Transfer Notice as reasonably
determined by the Company.

          (d) Condition to Transfer. All transferees of shares of Stock or any
interest therein other than the Company shall be required as a condition of such
transfer to agree in writing (in a form satisfactory to the Company) that they
will receive and hold such shares of Stock or interests subject to the
provisions of this Agreement, including the Right of First Refusal.

          (e) Assignment of Right of First Refusal. The Company may assign the
Right of First Refusal to one or more persons, who shall have the right to
exercise the Right of First Refusal in his or her own name for his or her own
account.

          (f) Termination. The Right of First Refusal will terminate upon the
closing of a firm commitment underwritten public offering to the public of the
Company's Common Stock pursuant to a registration statement under the Securities
Act of 1933, as amended (the "IPO").

          (g) Transfer Not Subject to Right of First Refusal. The Right of First
Refusal shall not apply to a transfer of shares of the Stock to the Founder's
ancestors, descendants or spouse or to a trustee for their benefit or the
benefit of the Founder, provided that such transferee shall agree in writing (in
a form satisfactory to the Company) to take the shares of Stock subject to all
the terms and conditions of this Section 3.

     4. Piggyback Registration Rights.

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<PAGE>   5

          (a) If the Company shall determine to register any of its securities
either for its own account or the account of a shareholders) exercising demand
registration rights, other than a registration relating solely to employee
benefit plans, or a registration relating solely to a transaction pursuant to
Rule 145 promulgated under the Securities Act of 1933, or a registration on any
registration form which does not permit secondary sales or does not include
substantially the same information as would be required to be included in a
registration statement covering the sale of the Stock, the Company will promptly
give to the Founder written notice thereof and include in such registration (and
any related qualification under blue sky laws), and in any underwriting involved
therein, the number of Vested Shares specified in a written request made by the
Founder within fifteen (15) days after receipt of such written notice from the
Company, except as set forth in Section 4(b) below.

          (b) If the registration of which the Company gives notice is for a
registered public offering involving an underwriting, the right of any Founder
to registration shall be conditioned upon the Founder's participation in such
underwriting and the inclusion of such Founder's Stock in the underwriting
pursuant to an underwriting agreement in customary form with the underwriter or
underwriters selected by the Company. Notwithstanding any other provision of
this Section, if the underwriter reasonably determines that marketing factors
require a limitation on the number of shares to be underwritten the underwriter
may exclude some or all of the Stock with the number of shares that may be
included in the registration and underwriting being allocated among the Founder
and all other shareholders entitled to have securities included in such
registration in proportion, as nearly as practicable, to the respective amounts
of securities which they had requested to be included in such registration
(provided, however, that if the registration is for the account of shareholders
exercising demand registration rights, the number of shares that may be included
by the Founder shall be cut back entirely before any limitation on the number of
shares that may be included by such shareholders).

          (c) All expenses of the registration shall be borne by the Company,
except underwriting discounts and selling commissions applicable to the sale of
any of Founder's Stock and any other securities of the Company being sold in the
same registration by other shareholders, which shall be borne by the Founder and
such other shareholders pro rata on the basis of the number of their shares
registered.

     5. Stock Dividends, etc. If, from time to time, there is any stock
dividend, stock split or other change in the character or amount of any of the
outstanding stock of the Company, then in such event any and all new substituted
or additional securities to which Founder is entitled by reason of Founder's
ownership of Unvested Shares or Stock shall be immediately subject to the
Unvested Share Repurchase Option or the Right of First Refusal, respectively,
with the same force and effect as the Unvested Shares or Stock.

     6. Consent of Spouse. If the Founder is married on the date of this
Agreement, the Founder's spouse shall execute a Consent of Spouse in the form of
Exhibit A hereto, effective on the date hereof. Such consent shall not be deemed
to confer or convey to the spouse any rights in the Stock that do not otherwise
exist by operation of law or the agreement of the parties. If the Founder should
marry or remarry subsequent to the date of this Agreement, the Founder shall
within thirty (30) days thereafter obtain his or her new spouse's acknowledgment
of and consent

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<PAGE>   6

to the existence and binding effect of all restrictions contained in this
Agreement by signing an additional Consent of Spouse in the form of Exhibit A.

     7. Legends. All certificates representing any shares of Stock subject to
the provisions of this Agreement shall have endorsed thereon the following
legends:

          (a) "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A
REPURCHASE OPTION AND RIGHT OF FIRST REFUSAL IN FAVOR OF THE COMPANY OR ITS
ASSIGNEE SET FORTH IN AN AGREEMENT BETWEEN THE COMPANY AND THE REGISTERED
HOLDER, OR HIS OR HER PREDECESSOR IN INTEREST, A COPY OF WHICH IS ON FILE AT THE
PRINCIPAL OFFICE OF THIS COMPANY.

          (b) "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD,
TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE REGISTRATION
STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE IN
ACCORDANCE WITH RULE 144 UNDER THE ACT, OR THE COMPANY RECEIVES AN OPINION OF
COUNSEL FOR THE HOLDER OF THESE SECURITIES REASONABLY SATISFACTORY TO THE
COMPANY, STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT
FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT."

          (c) Any legend required to be placed thereon by the federal or state
securities authorities.

     8. Warranties and Representations. In connection with the proposed purchase
of the Stock, the Founder hereby agrees, represents and warrants as follows:

          (a) The Founder is purchasing the Stock solely for his own account for
investment and not with a view to, or for resale in connection with, any
distribution thereof within the meaning of the Securities Act of 1933 as amended
(the "Act"). The Founder further represents that he or she does not have any
present intention of selling, offering to sell or otherwise disposing of or
distributing the Stock or any portion thereof; and that the entire legal and
beneficial interest of the Stock he or she is purchasing is being purchased for,
and will be held for the account of, the Founder only and neither in whole nor
in part for any other person.

          (b) The Founder is aware of the Company's business affairs and
financial condition and has acquired sufficient information about the Company to
reach an informed and knowledgeable decision to acquire the Stock. The Founder
further represents and warrants that he or she has discussed the Company and its
plans, operations and financial condition with its officers, has received all
such information as he or she deems necessary and appropriate to enable him or
her to evaluate the financial risk inherent in making an investment in the Stock
and has received satisfactory and complete information concerning the business
and financial condition of the Company in response to all inquiries in respect
thereof.

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<PAGE>   7

          (c) The Founder realizes that his or her purchase of the Stock will be
a highly speculative investment, and he is able, without impairing his financial
condition, to hold the Stock for an indefinite period of time and to suffer a
complete loss on his investment.

          (d) The Company has disclosed to the Founder that:

               (i) The sale of the Stock has not been registered under the Act,
and the Stock, must be held indefinitely unless a transfer of it is subsequently
registered under the Act or an exemption from such registration is available,
and that the Company is under no obligation to register the Stock;

               (ii) The Company will make a notation in its records of the
aforementioned restrictions on transfer and legends.

     9. Escrow. As security for his faithful performance of the terms of this
Agreement and to ensure the availability for delivery of the Stock upon exercise
of the Unvested Share Repurchase Option and the Right of First Refusal herein
provided for, the Founder agrees to deliver to and deposit with Gray Cary Ware &
Freidenrich, a Professional Corporation (the "Escrow Agent"), as Escrow Agent in
this transaction, two Stock Assignments duly endorsed (with date and number of
shares blank) in the form attached hereto as Exhibit B. together with the
certificate or certificates evidencing the Stock. Such documents shall be held
by the Escrow Agent pursuant to the Joint Escrow Instructions of the Company and
the Founder set forth in Exhibit C attached hereto and incorporated by this
reference, which instructions shall also be delivered to the Escrow Agent at the
closing hereunder.

     10. Transfers in Violation of Agreement. The Company shall not be required
(i) to transfer on its books any shares of Stock of the Company which shall have
been sold or transferred in violation of any of the provisions set forth in
this Agreement or (ii) to treat as owner of such shares or to accord the right
to vote as such owner or to pay dividends to any transferee to whom such shares
shall have been so transferred.

     11. Rights as Shareholder. Subject to the provisions of this Agreement, the
Founder shall exercise all rights and privileges of a shareholder of the Company
with respect to the Stock deposited in escrow.

     12. Further Instruments. The parties agree to execute such further
instruments and to take such further action as may reasonably be necessary to
carry out the intent of this Agreement.

     13. "Market Stand-Off" Agreement. Founder hereby agrees that in connection
with the IPO, during the period of duration (not to exceed 180 days) specified
by the Company and an underwriter of common stock of the Company following the
effective date of the registration statement of the Company filed under the
Securities Act with respect to the IPO, he shall not, to the extent requested by
the Company and such underwriter, directly or indirectly sell, offer to sell,
contract to sell (including, without limitation, any short sale), grant any
option to purchase, pledge or otherwise transfer or dispose of (other than to
donees who agree to be similarly bound) any securities of the Company held by
him at any time during such period except common stock

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<PAGE>   8

included in such registration. Founder agrees to the terms of any form of such a
stand-off agreement as approved by the company or the underwriter of the IPO.

     14. Notice. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery, upon
deposit in the United States Post Office, by registered or certified mail with
postage and fees prepaid, or upon delivery to an overnight courier service
addressed to the other party at the address hereinafter shown below his
signature or at such other address as such party may designate by ten (10)
days' advance written notice to the other party.

     15. Successors and Assigns. This Agreement shall inure to the benefit of,
and be binding upon, the successors and assigns of each party, including,
without limitation, in the case of the Founder, Founder's heirs, executors,
administrators, successors and assigns.

     16. Entire Agreement; Amendments. This Agreement, together with the
Exhibits hereto, shall be construed under the laws of the State of California
(as it applies to agreements between California residents, entered into and to
be performed entirely within California), and constitutes the entire agreement
of the parties with respect to the subject matter hereof superseding all prior
written or oral agreements, and no amendment or addition hereto shall be deemed
effective unless agreed to in writing by the parties.

     17. Right to Specific Performance. The Founder agrees that the Company
shall be entitled to a decree of specific performance of the terms hereof or an
injunction restraining violation of this Agreement, said right to be in addition
to any other remedies available to the Company.

     18. Separability. If any provision of this Agreement is held by a court of
competent jurisdiction to be invalid, void or unenforceable, the remaining
provisions shall nevertheless continue in full force and effect without being
impaired or invalidated in any way and shall be construed in accordance with the
purposes and tenor and effect of this Agreement.

     19. Tax Consequences and Tax Election Notification.

          (a) The Founder understands that Section 83 of the Internal Revenue
Code of 1986, as amended (the "Code") taxes as ordinary income the difference
between the amount paid for the Stock and the fair market value of the Stock as
of the date any restrictions on the Stock lapse. In this context, "restriction"
means the right of the Company to buy back the stock pursuant to the Unvested
Share Repurchase Option. The Founder understands that he or she may elect to be
taxed at the time the Stock is purchased rather than when and as the Unvested
Share Repurchase Option expires by filing an election under Section 83(b) of the
Code with the Internal Revenue Service (the "IRS") within 30 days from the date
of purchase. Even if the fair market value of the Stock equals the amount paid
for the Stock, the election must be made to avoid adverse tax consequences in
the future. The Founder understands that failure to make this filing timely will
result in the recognition of ordinary income by the Founder, as the Unvested
Share Repurchase Option lapses, on the difference between the purchase price and
the fair market value of the Stock at the time such restriction lapses.

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<PAGE>   9

          (b) The Founder understands that the purchase price of the Stock has
been set by the Board of Directors and that the Company believes this valuation
is a fair attempt to appraise it. The Founder understands, however, that if the
Founder files a Section 83(b) election, the Company can give no assurances that
the purchase price will be accepted as the fair market value of the Stock by the
IRS, and that the IRS could assert that the value of the Stock on the date of
purchase was substantially greater than the purchase price.

          If the IRS were to successfully argue in a tax determination that the
Stock had a value greater than the price paid by the Founder, and the Founder
has filed a Section 83(b) election, the additional value would constitute
ordinary income as of the date of its receipt. The additional taxes (and
interest) due would be payable by the Founder. There is no provision for the
Company to reimburse the Founder for any potential tax liability, and the
Founder assumes all responsibility for any such liability. If the additional
value attributed to the Stock was more than 25 percent of the Founder's gross
income for the year in which that value was taxable, the IRS would have six
years from the due date for filing of the Founder's the return (or the actual
filing date of the return if filed thereafter) within which to assess the
additional tax and interest.

     THE FOUNDER ACKNOWLEDGES THAT IT IS THE FOUNDER'S SOLE RESPONSIBILITY AND
NOT THE COMPANY'S RESPONSIBILITY TO FILE TIMELY THE ELECTION UNDER SECTION
83(b), EVEN IF THE FOUNDER REQUESTS THE COMPANY OR ITS REPRESENTATIVES TO MAKE
TIES FILING ON THE FOUNDER'S BEHALF. THE FOUNDER FURTHER UNDERSTANDS THAT ANY
PURPORTED ELECTION PURSUANT TO SECTION 83(b) MUST COMPLY WITH THE PROVISIONS OF
TREASURY REGULATION SECTION 1.83-2. FOUNDER ACKNOWLEDGES THAT HE HAS BEEN
ADVISED BY THE COMPANY TO SEEK THE ASSISTANCE OF A TAX ADVISOR IN THIS MATTER.

          (c) The Founder shall notify the Company in writing if Founder files
an election pursuant to Section 83(b) of the Code. The Company intends, in the
event it does not receive from Founder evidence of such filing, to claim a tax
deduction for any amount which would be taxable to Founder in the absence of
such an election.

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the day and year first above written.

"FOUNDER"                               "COMPANY"

                                        MachOne Communications, Inc.

/s/ MATTHEW J. STEPOVICH                By: [SIGNATURE ILLEGIBLE]
-------------------------------------       ---------------------------------

Address: 26-1/2 Ashler Ave.             Title: CEO
         ----------------------------          ------------------------------

         Los Gatos,  CA 95030
         ----------------------------

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<PAGE>   10

                                    EXHIBIT A

                                CONSENT OF SPOUSE

          I, _______________ spouse of _______________, acknowledge that I have
read the Founder Stock Purchase Agreement dated as of _____________, 1998, to
which this Consent is attached as Exhibit A (the "Agreement") and that I know
its contents. I am aware that by its provisions the Company has the option to
purchase certain shares of Stock of the Company which my spouse owns pursuant to
the Agreement including any interest I might have therein, upon termination of
his employment under circumstances set forth in the Agreement, and that certain
other restrictions are imposed upon the sale or other disposition of the Stock
during my spouse's lifetime and in the event of his death.

     I agree that my interest, if any, in the Stock subject to the Agreement
shall be bound by the Agreement and further understand and agree that any
community property interest I may have in the Stock shall be similarly bound by
the Agreement.

     Signed and Dated:
                      ----------------------

                                       10
<PAGE>   11

                                    EXHIBIT B

                      ASSIGNMENT SEPARATE FROM CERTIFICATE

          FOR VALUE RECEIVED, ________________ hereby sells, assigns and
transfers unto __________________ _________________ (___) shares of the Common
Stock of MachOne Communications, Inc., a California corporation, standing in the
undersigned's name on the books of said corporation represented by Certificate
No. _____ herewith, and do hereby irrevocably constitute and appoint
________________ attorney to transfer the said stock on the books of the said
corporation with full power of substitution in the premises.

Date: June __, 1998                     By:
                                           ----------------------------------<PAGE>   1

                                                                   EXHIBIT 10.21

                                LEASE AGREEMENT

                                     BETWEEN

                               KRAMER 34 HP, LTD.

                                  as Landlord,

                                       and

                        IXC COMMUNICATIONS SERVICES, INC.

                                   as Tenant,

                              Covering the Building
                            known (or to be known) as

                                    KRAMER 3

                                   located at

                          1825-A KRAMER LANE, SUITE 100

                               Austin, Texas 78758

<PAGE>   2

                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                         PAGE NO.
<S>     <C>                                                                              <C>
1.       PREMISES, TERM, AND IMPROVEMENTS.......................................................1
2.       BASE RENT, ADDITIONAL RENT AND SECURITY DEPOSIT........................................1
3.       TAXES..................................................................................2
4.       LANDLORD'S MAINTENANCE.................................................................2
5.       TENANT'S MAINTENANCE AND REPAIR OBLIGATIONS............................................3
6.       ALTERATIONS............................................................................3
7.       SIGNS..................................................................................3
8.       UTILITIES..............................................................................3
9.       INSURANCE..............................................................................3
10.      CASUALTY DAMAGE........................................................................4
11.      LIABILITY, INDEMNIFICATION, WAIVER OR SUBROGATION AND NEGLIGENCE.......................4
12.      USE....................................................................................5
13.      INSPECTION.............................................................................5
14.      ASSIGNMENT AND SUBLETTING..............................................................5
15.      CONDEMNATION...........................................................................6
16.      SURRENDER OF PREMISES; HOLDING OVER....................................................6
17.      QUIET ENJOYMENT........................................................................7
18.      EVENTS OF DEFAULT......................................................................7
19.      REMEDIES...............................................................................7
20.      LANDLORD'S DEFAULT.....................................................................8
21.      MORTGAGES..............................................................................8
22.      ENCUMBRANCES...........................................................................8
23.      MISCELLANEOUS..........................................................................8
24.      NOTICES...............................................................................10
25.      HAZARDOUS WASTE.......................................................................10

</TABLE>

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<PAGE>   3

                              LIST OF DEFINED TERMS
<TABLE>

<S>                                                                                          <C>
Lease..........................................................................................1
Landlord.......................................................................................1
Tenant.........................................................................................1
Premises.......................................................................................1
Building.......................................................................................1
Land...........................................................................................1
Proportionate Share............................................................................1
Commencement Date..............................................................................1
Term...........................................................................................1
Shell Improvements.............................................................................1
Base Rent......................................................................................1
Operating Expenses.............................................................................1
Rent...........................................................................................2
Taxes..........................................................................................2
Building's Structure...........................................................................2
HVAC Systems...................................................................................3
Repair Period..................................................................................4
Vacation Date..................................................................................5
Transfer.......................................................................................5
Taking.........................................................................................6
Event of Default...............................................................................7
Claimant.......................................................................................8
Mortgage.......................................................................................8
Primary Lease..................................................................................8
Landlord's Mortgagee...........................................................................8
Laws...........................................................................................8
Law............................................................................................9
Affiliate......................................................................................9
Tenant Party...................................................................................9
Including......................................................................................9
Hazardous Substances..........................................................................10
Environmental law.............................................................................10
Permitted Activities..........................................................................10
Permitted Materials...........................................................................10
MSDS..........................................................................................10
Working Drawings.............................................................................D-1
Initial Improvements.........................................................................D-1
Construction Allowance.......................................................................D-1
Total Construction Costs.....................................................................D-1

</TABLE>

                                        3

<PAGE>   4

                                 LEASE AGREEMENT

         This Lease Agreement (this "LEASE") is entered into by Kramer 34 HP,
Ltd., ("Landlord"), and IXC Communications Services, Inc., ("Tenant").

         1.       PREMISES, TERM AND IMPROVEMENTS.

                  (a) Landlord leases to Tenant, and Tenant leases from
Landlord, the space depicted on the floor plan attached as EXHIBIT A-1 (the
"PREMISES"), which is part of the approximately 62,167 square foot building (the
"BUILDING") located on the real property described on EXHIBIT A (the "LAND"),
subject to the terms and conditions in this Lease. The Building is a part of the
seven (7) building project known as Braker Center IV, as more particularly shown
on EXHIBIT A-2 attached hereto (the "PROJECT"). Landlord and Tenant stipulate
that, as of the date of this Lease, the size of the Premises is 24,682 square
feet (subject to increase as provided on Exhibit C) and the size of the Building
is 62,167 square feet, and Tenant's initial "PROPORTIONATE SHARE" is 39.7%. The
size of the Premises and Proportionate Share shall be adjusted if the size of
the Premises changes, including, without limitation, increases in the Premises
due to Tenant's lease of the Expansion Space as provided on EXHIBIT C.

                  (b) The Lease term shall be sixty (60) months, beginning on
the later of (i) sixty (60) days after the date of substantial completion of the
Shell Improvements (as defined on EXHIBIT B) or (ii) November 15, 1999 (the
"COMMENCEMENT DATE"), and ending November 14, 2004 (the "TERM"), which defined
term shall include all renewals and extensions of the Term, if any).
Notwithstanding the foregoing if the Commencement Date does not occur on
November 15, 1999, then the Term shall end sixty (60) months after the first day
of the first full calendar month after the Commencement Date.

                  (c) Landlord shall construct the shell improvements (the
"SHELL IMPROVEMENTS") described on EXHIBIT B, and, by occupying the Premises,
Tenant shall have accepted the Premises in their shell condition, subject to
completion of any punch-list items relating to the Shell Improvements. Tenant
shall be responsible for constructing the Initial Improvements described on the
plans and specifications referenced on Exhibit B.

         2        BASE RENT, ADDITIONAL RENT AND SECURITY DEPOSIT.

                  (a) Tenant shall pay to Landlord "BASE RENT", in advance,
without demand, deduction or set off, equal to the following amounts for the
following periods of time:

        TIME PERIOD                MONTHLY BASE RENT
        Months 1 through 24        $.82 per square foot of the Premises
        Months 25 through 36       $.84 per square foot of the Premises
        Months 37 through 60       $.86 per square foot of the Premises

The first monthly installment, plus the other monthly charges set forth in
Section 2(b.), shall be due on the date hereof; thereafter, monthly installments
of Base Rent shall be due on the first day of each calendar month following the
Commencement Date. If the Term begins on a day other than the first day of a
month or ends on a day other than the last day of a month, the Base Rent and
additional rent for such partial month shall be prorated.

                  (b) Tenant shall pay, as additional rent its Proportionate
Share of all costs incurred in operating, managing, and maintaining the
Premises, the Land and the Building and the facilities and services provided for
the common use of Tenant and any other tenants of the Building (collectively,
"OPERATING EXPENSES"), including the following items: (1) Taxes (defined below)
and the cost of any tax consultant employed to assist Landlord in determining
the fair tax valuation of the Building and Land; (2) the cost of all utilities
used in the Building which are not billed separately to a tenant for above
building standard utility consumption; (3) the cost of insurance; (4) the cost
of repairs, replacement, management fees and expenses, landscape maintenance and
replacement, security service (if provided), trash service (if provided); (5)
the cost of dues, assessments, and other charges applicable to the Land payable
to any property or community owner association under restrictive covenants or
deed restrictions to which the Land is subject; (6) maintenance of the
Building's fire sprinkler systems; and (7) alterations, additions, and
improvements made by Landlord to comply with Law (defined below) or in order to
reduce Operating Expenses. On the same day that Base Rent is due, Tenant shall
pay to Landlord an amount equal to 1/12 of Landlord's estimate of Tenant's
Proportionate Share of annual Operating Expenses. The initial monthly payments
are based upon Landlord's estimate of the Operating Expenses for the year in
question, and shall be increased or decreased annually to reflect the projected
actual Operating Expenses for that year. Within 90 days after each calendar year
or as soon thereafter as is reasonably practicable, Landlord shall deliver to
Tenant a statement setting forth the actual Operating Expenses for such year. If
Tenant's total payments in respect of Operating Expenses for any year are less
than Tenant's Proportionate Share of Operating Expenses for that year, Tenant
shall pay the difference to Landlord within 30 days after Landlord's request
therefor; if such payments are more than Tenant's Proportionate Share of
Operating Expenses, Landlord shall retain such excess and credit it against
Tenant's future annual payments monthly payments, except that any credit
remaining at the expiration or earlier termination of this Lease shall be paid
to Tenant within thirty (30) days after such expiration or termination,
notwithstanding the foregoing, the initial Operating Expenses and Taxes
described in this Section 2(b.) will be deemed to be the actual amounts owed by
Tenant (and not subject to adjustments if the actual

                                        1

<PAGE>   5

Operating Expenses and Taxes are less until such time as Tenant leases the
expansion space. Expenses shall not include the following: (A) any costs for
interest, amortization, or other payments or loans to Landlord; (B) commissions
or other expenses incurred in leasing or procuring tenants; (C) legal expenses
other than those incurred for the direct benefit of the tenants of the Building;
(D) allowances, concessions, and other costs of renovating or otherwise
improving space for occupants of the Building or vacant space in the Building;
(E) federal income taxes imposed on or measured by the income of Landlord from
the operation of the Building; (F) rents under ground leases; (G) costs incurred
in selling, syndicating, financing, mortgaging, or hypothecating any of
Landlord's interests in the Building. There shall be no duplication of costs for
reimbursements in calculating Operating Expenses; and (H) costs of capital
improvements except for those provided in (7) above and except that Landlord may
include in Operating Expenses only such portion of capital improvement costs as
is necessary to amortize such improvements over their useful life. The amounts
of the initial monthly Base Rent and Tenant's Proportionate Share of Operating
Expenses (and the part thereof attributable to Taxes) are as follows:

<TABLE>

        <S>                                                              <C>
         Base Rent (Section 2(a)..........................................$   22,239.29
         Operating Expenses, excluding Taxes (Section 2(b))...............$    1,999.24
         Taxes (Sections 2.(b) and 3......................................$    2,438.58

         Total initial monthly payment....................................$   24,677.06

</TABLE>

                  (c) If any payment required of Tenant under this Lease is not
paid within fifteen (15) days after due, Landlord may charge Tenant a fee equal
to 5% of the delinquent payment to reimburse Landlord for its cost and
inconvenience incurred as a consequence of Tenant's delinquency; provided,
however, that if Tenant is late more than three (3) times in any given 12 month
period, then subsequent to any such third late payment any failure to pay rent
or any other sum when due shall be subject to the foregoing late fee immediately
(i.e., without the 15-day grace period).

                  (d) All payments and reimbursements required to be made by
Tenant under this Lease shall constitute "RENT" (herein so called).

                  (e) Landlord shall keep good and accurate books and records in
accordance with sound accounting principles consistently applied concerning the
Operating Expenses, and Tenant shall have the right, upon 10 days notice, to
inspect and copy such books and records. In any event, Landlord shall credit
Tenant in the same manner as overpayments of Operating Expenses per subparagraph
(b) above all Operating Expenses shown by such inspection to have been overpaid
by Tenant, as mutually determined by Landlord and Tenant in good faith, and,
similarly, Tenant shall promptly pay Landlord all Operating Expenses shown by
such inspection to have been underpaid by Tenant, as mutually determined by
Landlord and Tenant in good faith. Tenant shall not have the right to conduct
any such inspection more frequently than once annually or for periods prior to
the immediately preceding lease year. Landlord shall reimburse Tenant for the
audit expense if any overpayment is found to be 10% or greater.

         3.       TAXES.

                  (a) Landlord shall pay all taxes, assessments and governmental
charges whether federal, state, county, or municipal and whether they are
imposed by taxing or management districts or authorities presently existing or
hereafter created (collectively, "TAXES") that accrue against the Premises, the
Land and the Building. If, during the Term, there is levied, assessed or imposed
on Landlord a capital levy or other tax directly on the rent or a franchise tax,
assessment, levy or charge measured by or based, in whole or in part, upon rent,
then all such taxes, assessments, levies or charges, or the part thereof so
measured or based, shall be included within the term "Taxes".

                  (b) Tenant shall (1) before delinquency pay all taxes levied
or assessed against any personal property, fixtures or alterations placed in the
Premises and (2) upon the request of Landlord, deliver to Landlord receipts from
the applicable taxing authority or other evidence acceptable to Landlord to
verify that such taxes have been paid. If any such taxes are levied or assessed
against Landlord or Landlord's property and (A) Landlord pays them or (B) the
assessed value of Landlord's property is increased thereby and Landlord pays the
increased taxes, then Tenant shall pay to Landlord such taxes within ten days
after Landlord's request therefor.

         4. LANDLORD'S MAINTENANCE.

                  (a) This Lease is intended to be a net lease; accordingly,
Landlord's maintenance obligations are limited to the replacement of the
Building's roof and maintenance of the foundation piers and structural members
of the exterior walls (collectively, the "BUILDING'S STRUCTURE"); however,
Landlord shall not be responsible for alterations to the Building's Structure
required by Law because of Tenant's use of the Premises (which alternations
shall be performed by Tenant). Landlord's liability for any defects, repairs,
replacement or maintenance for which Landlord is responsible hereunder shall be
limited to the cost of performing such work.

                  (b) Additionally, Landlord shall, maintain the parking areas,
driveways, alleys and grounds surrounding the Premises in a clean and sanitary
condition, consistent with the operation of a first-class office/warehouse
building, including prompt maintenance, repairs and replacements of (1) any
drill or spur tract servicing the Premises, (2) the exterior of the Building
(including painting), (3) sprinkler systems and sewage lines, and (4) any other
items normally associated with the foregoing. Tenant shall promptly notify
Landlord of any work required to be performed under this Section 4(b.), and
Landlord shall not be responsible for performing such work until Tenant delivers
to landlord such notice. All costs in performing the work described in this
Section 0 shall be included in Operating Expenses, subject to the applicable
provisions of Section 2(b) hereof.

                                        2

<PAGE>   6

                  (c) Additionally, Landlord shall maintain the private entry
drive, the detention pond, and other common areas for the Project as shown on
Exhibit A-2. The Building's Proportionate Share of all costs in performing the
work described in this Section 4(c) shall be included in Operating Expenses,
subject to the applicable provisions of Section 2(b) hereof. As used herein, the
term "Building's Proportionate Share" shall be a fraction which is determine by
dividing the number of square feet contained in the Building (62,167) by the
number of square feet then contained in the Project. Currently there are 167,311
square feet in the Project, and therefore the initial Building's Proportionate
Share is 37.15%. As additional square footage,in the Project is completed and
ready for occupancy, the number of square feet in the Project will be increased
and the Building's Proportionate Share will be adjusted accordingly.

         5.       TENANT'S MAINTENANCE AND REPAIR OBLIGATIONS.

                  (a) Tenant shall maintain all parts of the Premises [except
for maintenance work which Landlord is expressly responsible for under Section
4(a.) in good condition and promptly make all necessary repairs and replacements
to the Premises, normal wear and tear and damage by casualty excepted. Tenant
shall repair and pay for any damage caused by a Tenant Party (defined below) or
caused by Tenant's default hereunder.

                  (b) Tenant shall maintain the hot water equipment and the
heating, air condition, and ventilation equipment and system the "HVAC SYSTEM")
in good repair and condition and in accordance with Law and with such equipment
manufacturers' suggested operation/maintenance service program; such obligation
shall include replacement of all equipment necessary to maintain such equipment
and system in good working order. Within ten days after the Commencement Date.
At least 14 days before the end of the Term, Tenant shall deliver to Landlord a
certificate from an engineer reasonably acceptable to Landlord certifying that
the hot water equipment and the HVAC System are then in good repair and working
order.

         6. ALTERATIONS. Tenant shall not make any alterations, additions or
improvements to the Premises without the prior written consent of Landlord.
Landlord shall not be required to notify Tenant of whether it consents to any
alteration, addition or improvements until it (a) has received plans and
specifications therefor which are sufficiently detailed to allow construction of
the work depicted thereon to be performed in a good and workmanlike manner, and
(b) has had five (5) business days to review them. If the alteration, addition
or improvement will affect the Building's Structure, HVAC System, or mechanical,
electrical, or plumbing systems, then the plans and specifications therefor must
be prepared by a licensed engineer reasonably acceptable to Landlord. Landlord's
approval of any plans and specifications shall not be a representation that the
plans or the work depicted thereon will comply with law or be adequate for any
purpose, but shall merely be Landlord's consent to performance of the work. Upon
completion of any alteration, addition, or improvement, Tenant shall deliver to
Landlord accurate, reproducible as-built plans therefor. Tenant may erect
shelves, bins, machinery and trade fixtures provided that such items (1) do not
alter the basic character of the Premises; (2) do not overload or damage the
same; and (3) may be removed without damage to the Premises. Unless Landlord
specifies in writing otherwise, all alterations, additions, and improvements
shall be Landlord's property when installed in the Premises. All work performed
by a Tenant Party in the Premises (including that relating to the installations,
repair, replacement, or removal of any item) shall be performed in accordance
with Law and with Landlord's specifications and requirements, in a good and
workmanlike manner, and so as not to damage or alter the Building's Structure or
the Premises. Tenant shall be responsible for compliance with American With
Disabilities Act of 1990 for the interior, non-structural portions of the
Premises, Landlord shall be responsible for compliance with the American With
Disabilities Act of 1990 relative to the Building's Structure, unless such
compliance is required solely in connection with a Tenant alteration of the
Building, in which case such compliance shall be Tenant's responsibility.

         7. SIGNS. Tenant shall not place, install or attach any signage,
decorations, advertising media, blinds, draperies, window treatments, bars, or
security installations to the Premises or the Building without Landlord's prior
written approval. Landlord hereby agrees that Tenant may erect such signage as
is shown on the Plans approved by Landlord in accordance with Exhibit B attached
hereto. Tenant shall repair, paint, and/or replace any portion of the Premises
or the Building damaged or altered as a result of its signage when it is removed
(including, without limitation, any discoloration of the Building). Tenant shall
not (a) make any changes to the exterior of the Premises or the Building, (b)
install any exterior lights, decorations, balloons, flags, pennants, banners or
paintings, or (c) erect or install any signs, windows or door lettering, decals,
window or storefront stickers, placards, decorations or advertising media of any
type that is visible from the exterior of the Premises or the Building without
Landlord's prior written consent. Landlord shall not be required to notify
Tenant of whether it consents to any sign until it (1) has received detailed,
to-scale drawings thereof specifying design, material composition, color scheme,
and method of installation, and (2) has had a reasonable opportunity to review
them.

         8. UTILITIES. Tenant shall pay directly to the utility provider all
electricity and telephone charges used at the Premises, together with any taxes,
penalties, surcharges, maintenance charges, and the like pertaining thereto.
Tenant shall obtain telephone and computer line service tor the Premises.
Landlord shall provide, as part of the Initial Improvements, all other utility
service and connections to the Premises, including water, gas, electricity and
sewer. Except for electricity and telephone service, Tenant's use of all
utilities shall be part of Operating Expenses; provided, however, if Tenant's
use of any utility exceeds building- standard service, Landlord may, at Tenant's
expense, separately meter and bill Tenant directly for its use of any such
utility service, in which case, the amount separately billed to Tenant for above
building-standard utility service shall not be duplicated in Tenant's obligation
to pay additional rent under Section 2.(b). Landlord shall not be liable for any
interruption or failure of utility service to the Premises, unless caused by
Landlord. Landlord shall grant access to the Premises for telecom providers
designated by

                                        3

<PAGE>   7

Tenant on the same terms as other current providers of such service. All amounts
due Landlord from Tenant under this Section 8 shall be payable within ten days
after Landlord's request therefor.

         9. INSURANCE. Tenant shall maintain (a) workers' compensation insurance
(with a waiver of subrogation endorsement reasonably acceptable to Landlord and
commercial general liability insurance (with contractual liability endorsement),
including personal injury and property damage in the amount of $1,000,000 per
occurrence combined single limit for personal injuries and death of persons and
property damage occurring in or about the Premises, plus umbrella coverage of at
least $2,000,000 per occurrence, (b) fire and extended coverage insurance
covering (1) the replacement cost of all alterations, additions, partitions and
improvements installed in the Premises, (2) the replacement cost of all of
Tenant's personal property in the Premises, and (3) loss of profits in the event
of an insured peril damaging the Premises, and (c) such other insurance as
Landlord may reasonably require. Such policies shall (A) name Landlord,
Landlord's agents, and their respective Affiliates (defined below), as
additional insurers (and as loss payees on the fire and extended coverage
insurance), (3) be issued by an insurance company acceptable to Landlord, (C)
provide that such insurance may not be cancelled unless 30-days prior written
notice is first given to Landlord, (D) be delivered to Landlord by Tenant before
the Commencement Date and at least 15 days before each renewal thereof, and (E)
provide primary coverage to Landlord when any policy issued to Landlord is
similar or duplicate in coverage, in which case Landlord's policy shall be
excess over Tenant's policies.

         10.      CASUALTY DAMAGE.

                  (a) Tenant shall give written notice to Landlord of any damage
to the Premises or the Building promptly on discovery of the same. If the
Premises or the Building is totally destroyed by an insured peril, or so damaged
by an insured peril that, in Landlord's reasonable estimation, rebuilding or
repairs cannot be substantially completed within 90 days after the date of
Landlord's actual knowledge of such damage, then either Landlord or (if a Tenant
Party did not cause such damage) Tenant may terminate this Lease by delivering
to the other written notice thereof within 30 days after such damage, in which
case, the rent shall be abated from the date of occurrence through the unexpired
portion of this Lease, effective upon the date such damage occurred.
Time is of the essence with respect to the delivery of such notices.

                  (b) Subject to Section 10 (a.), if this Lease is not
terminated under Section 10 (a.), then Landlord shall restore the Premises to
substantially its previous condition, except that Landlord shall not be required
to rebuild, repair or replace any part of the partitions, fixtures, additions
and other improvements or personal property required to be covered by Tenant's
insurance under Section 9. If the Premises are untenable, in whole or in part,
during the period during the period beginning on the date such damage occurred
and ending on the date of substantial completion of Landlord's repair or
restoration work (the "REPAIR PERIOD") then the rent for such period shall be
reduced to such extent as may be fair and reasonable under the circumstances.

                  (c) If the Premises are destroyed or substantially damaged by
any peril not covered by the insurance maintained by Landlord or any Landlord's
Mortgage (defined below) requires that insurance proceeds be applied to the
indebtedness secured by its Mortgage (defined below) or to the Primary Lease
(defined below) obligations, Landlord may terminate this Lease by delivering
written notice of termination to Tenant within 30 days after such destruction or
damage or such requirement is made known by any such Landlord's Mortgagee, as
applicable, whereupon all rights and obligations hereunder shall cease and
terminate, except for any liabilities of Tenant which accrued before this Lease
is terminated, provided that all Base Rent and any additional rent accruing
after the date of the casualty shall be abated.

        11.   LIABILITY, INDEMNIFICATION, WAIVER OF SUBROGATION AND NEGLIGENCE.

                  (a) Landlord shall not be liable to Tenant or Tenant's agents,
employees or contractors, or those claiming by, through, or under any of them
for any Loss, except and only to the extent such Loss is caused solely by
Landlord's gross negligence or international misconduct. The term "LOSS" means
any injury to or death of any person or persons or any damage to or theft,
destruction, loss, or loss of use of any real or personal property caused by
casualty, theft, fire, or any acts or omissions of any person or party, and any
injury or damage or inconvenience which may arise through repair or alteration
of any part of the Premises, or failure to make repairs, or from any other
cause. In addition, Landlord and Tenant each waives any claims it might have
against the other for any damage to or theft, destruction, loss or loss of use
of any property, to the extent the same is insured against under any insurance
policy that covers the Premises, Landlord's or Tenant's fixtures, personal
property, leasehold improvements, or business, or is required to be insured
against by the party which might have such claim under the terms of this Lease,
regardless of whether the negligence (of whatever type or nature, including, but
not limited to, gross negligence) or fault of the other party caused such loss.
EACH PARTY SHALL CAUSE ITS INSURANCE CARRIER TO ENDORSE ALL APPLICABLE POLICIES
WAIVING THE CARRIER'S RIGHT OF RECOVERY UNDER SUBROGATION OR OTHERWISE AGAINST
THE OTHER PARTY.

                  (b) Subject to paragraph 11 (a), Tenant shall defend,
indemnify, and hold harmless Landlord and its agents and employees from and
against all claims, demands, liabilities, causes of action, suits, judgments,
attorney's fees and expenses for any Loss arising from any occurrence within, on
or about the Premises or arising from Tenant's failure to perform its
obligations under this Lease or arising from any act or omission (whether
negligent, intentional or otherwise) of Tenant or Tenant's agents, employees,
invitees or contractors, except to the extent that a Loss is caused solely by
the gross negligence or intentional misconduct of Landlord.

         Subject to paragraph 11 (a), Landlord shall defend, indemnify, and hold
harmless Tenant and its agents and

                                        4

<PAGE>   8

employees from and against all claims, demands, liabilities, causes of action,
suits, judgments, attorney's fees and expenses for any Loss arising from any
occurrence within, on or about the Premises, to the extent, and only to the
extent the Loss is caused solely by the gross negligence or intentional
misconduct of Landlord, or its agents, employees, invitees or contractors.

         THIS INDEMNITY PROVISION SHALL SURVIVE TERMINATION OR EXPIRATION OF
THIS LEASE.

         12.      USE.

                  (a) The Premises shall be used only for receiving, storing,
shipping and selling products, materials and merchandise made or distributed by
Tenant, for a data center and for such other lawful purposes as may be
incidental thereto; however, no retail sales may be made from the Premises.
Tenant shall not use the Premises to received, store or handle any product,
material or merchandise that is explosive or highly inflammable or hazardous.
Outside storage is prohibited. Tenant shall be solely responsible for complying
with all Laws applicable to the use, occupancy, and condition of the Premises;
provided, however, that Landlord shall deliver the Premises to Tenant in a
condition which is in compliance with all Laws. Tenant shall not permit any
objectionable or unpleasant odors, smoke, dust, gas, light, noise or vibrations
to emanate from the Premises; nor take any other action that would constitute a
nuisance or would disturb, unreasonably interfere with, or endanger Landlord or
any other person; nor permit the Premises to be used for any purpose or in any
manner that would (1) void the insurance thereon, (2) increase the insurance
risk, or (3) cause the disallowance of any sprinkler credits. Tenant shall pay
to Landlord on demand any increase in the cost of any insurance on the Premises
incurred by Landlord, which is caused by Tenant's use of the Premises or because
Tenant vacates the Premises.

                  (b) Tenant and its employees and invitees shall have the
non-exclusive right to use, in common with others, any parking areas associated
with the Premises which Landlord has designated for such use, subject to (1)
such reasonable rules and regulations as Landlord may promulgate from time to
time and (2) rights of ingress and egress of other tenants and their employees,
agents and invitees. Landlord agrees to provide at least one (1) parking space
for every three hundred (300) square feet of space leased within the Building
for the use of Tenant The Landlord further agrees to provide to the Tenant
parking equal to one (1) space per 250 square feet , should the Tenant no longer
use the Premises for the data center. The additional parking will be in the area
as described on Exhibit A-2 and will include all areas approved by the Landlord
or Tenant's parking needs.

                  (c) Landlord shall have the right to establish and amend form
time to time, rules and regulations governing all tenants' uses and occupancy of
the Building (provided the same are reasonable, non-discriminatory and uniformly
enforced), and provided further that in the event of a conflict between those
rules and this Lease, the Lease shall control.

         13. INSPECTION. Upon reasonable notice, Landlord and Landlord's agents
and representatives may enter the Premises during business hours to inspect the
Premises to make such repairs as may be required or permitted under this Lease;
to perform any unperformed obligations of Tenant hereunder; and to show the
Premises to prospective purchasers, mortgagees, ground lessors, and (during the
last 6 months of the Term) tenants. During the last 6 months of the Term,
Landlord may erect a sign on the Premises indicating that the Premises are
available. Tenant shall notify Landlord in writing of its intention to vacate
the Premises at least 60 days before Tenant will vacate the Premises; such
notice shall specify the date on which Tenant intends to vacate the Premises
(the "VACATION DATE"). At least 30 days before the Vacation Date, Tenant shall
arrange to meet with Landlord for a joint inspection of the Premises. After such
inspection, Landlord shall prepare a list of items that Tenant must perform
before the Vacation Date, which shall not include repairs due to normal wear and
tear or casualty. If Tenant fails to arrange for such inspection, then Landlord
may conduct such inspection and Landlord's determination of the work Tenant is
required to perform before the Vacation Date shall be conclusive. If Tenant
fails to perform such work before the Vacation Date, then Landlord may perform
such work at Tenant's cost. Tenant shall pay all costs incurred by Landlord in
performing such work within ten days after completion of the work and Landlord's
request therefor.

         14.      ASSIGNMENT AND SUBLETTING.

                  (a) Tenant shall not, without the prior written consent of
Landlord which will not be unreasonably withheld, (1) advertise that any portion
of the Premises is available for lease or cause or allow any such advertisement,
(2) assign, transfer, or encumber this Lease or any estate or interest herein,
whether directly or by operation of law, (3) permit any other entity to become
Tenant hereunder by merger, consolidation, or other reorganization; provided,
however, that such a transfer may occur without Landlord's consent so long as
the primary business of the new entity remains the same as Tenant's primary
business and the net worth of the new entity is equal or greater to that of
Tenant, (4) if Tenant is an entity other than a corporation whose stock is
publicly traded (or a corporation whose stock is in the process of being
publicly traded), permit the transfer of an ownership interest in Tenant so as
to result in a change in the current control of Tenant, (5) sublet any portion
of the Premises, (6) grant any license, concession, or other right of occupancy
of any portion of the Premises, or (7) permit the use of the Premises by any
parties other than Tenant (any of the events listed in Subparts 1 through 7
being a "TRANSFER"). If Tenant requests Landlord's consent to a Transfer, then
Tenant shall provide Landlord with a written description of all terms and
conditions of the proposed Transfer, copies of the proposed documentation, and
the following information about the proposed transferee: name and address;
reasonably satisfactory information about its business and business history; its

                                        5

<PAGE>   9

proposed use of the Premises; banking, financial, and other credit information;
and general references sufficient to enable Landlord to determine the proposed
transferee's creditworthiness and character. Tenant shall reimburse Landlord for
its reasonable attorneys' fees and other expenses incurred in connection with
considering any request for its consent to a Transfer. If Landlord consents to a
proposed Transfer, then the proposed transferee shall deliver to Landlord a
written agreement whereby it expressly assumes the Tenant's obligations
hereunder (however, any transferee of less than all of the space in the Premises
shall be liable only for obligations under this Lease that are properly
allocable to the space subject to the Transfer, and only to the extent of the
rent it has agreed to pay Tenant therefor). Landlord's consent to a Transfer
shall not release Tenant from performing its obligations under this Lease, but
rather Tenant and its transferee shall be jointly and severally liable therefor.
Landlord's consent to any Transfer shall not waive Landlord's rights as to any
subsequent Transfers. If an Event of Default occurs while the Premises or any
part thereof are subject to a Transfer, then Landlord, in addition to its other
remedies, may collect directly from such transferee all rents becoming due to
Tenant and apply such rents against Tenant's rent obligations. Tenant authorizes
its transferees to make payments of rent directly to Landlord upon receipt of
notice from Landlord to do so.

                  (b) Landlord may, within 30 days after submission of Tenant's
written notification of intent to Transfer, cancel this Lease (or, as to a
subletting or assignment, cancel as to the portion of the Premises proposed to
be sublet or assigned) effective 30 days after receiving notice of intent to
Transfer. If Landlord cancels this Lease as to any portion of the Premises, then
this Lease shall cease for such portion of the Premises and Tenant shall pay to
Landlord all rent accrued through the cancellation date relating to the portion
of the Premises covered by the proposed Transfer. Thereafter, Landlord may lease
such portion of the Premises to the prospective transferee (or to any other
person) without liability to Tenant.

                  (c) Tenant hereby assigns, transfers and conveys all
consideration received by Tenant under any Transfer, which are in excess of the
rents payable by Tenant under this Lease plus reasonable costs incurred by
Tenant in connection with such reletting. Tenant shall hold such amounts in
trust for Landlord and pay them to Landlord within ten days after receipt.

                  (d) Notwithstanding anything to the contrary contained in
subpart (2) of Section 14(a) above, Tenant may assign the Lease without
Landlord's consent to any of the following (a "Permitted Transferee"), provided
that the Permitted Transferee's financial condition, creditworthiness and
business reputation following the transfer are equal to or exceed those of
Tenant: (i) any successor corporation or other entity resulting from a merger or
consolidation of Tenant; (ii) any purchaser of all or substantially all of
Tenant's assets; or (iii) any entity which controls, is controlled by, or is
under common control with Tenant. Tenant shall give Landlord thirty (30) days
prior written notice of such assignment or sublease. Any Permitted Transferee
shall assume in writing all of Tenant's obligations under this Lease. Tenant
shall nevertheless at all times remain fully responsible and liable for the
payment of rent and the performance and observance of all of Tenant's other
obligations under this Lease. Nothing in this paragraph is intended to nor shall
permit Tenant to transfer its interest under this Lease as part of a fraud or
subterfuge to intentionally avoid its obligations under this Lease (for example,
transferring its interest to a shell corporation that subsequently files a
bankruptcy), and any such transfer shall constitute an Event of Default
hereunder.

         15. CONDEMNATION. If more than 50% of the Premises or 25% of the
Building or Land is taken for any public or quasi-public use by right of eminent
domain or private purchase in lieu thereof (a "TAKING"), and the Taking prevents
or materially interferes with the use of the Premises for the purpose for which
they were leased to Tenant, (including a data center) either party may terminate
this Lease by delivering to the other written notice thereof within 30 days
after the Taking, in which case rent shall be abated during the unexpired
portion of the Term, effective on the date of such Taking. If (a) less than 50%
of the Premises or 25% of the Building or Land are subject to a Taking or (b)
more than 50% of the Premises or 25% of the Building or Land are subject to a
Taking, but the Taking does not prevent or materially interfere with the use of
the Premises for the purpose for which they were leased to Tenant (including a
data center), then neither party may terminate this Lease, but the rent payable
during the unexpired portion of the Term shall be reduced to such extent as may
be fair and reasonable under the circumstances. All compensation awarded for any
Taking shall be the property of Landlord and Tenant assigns any interest it may
have in any such award to Landlord; however, Landlord shall have no interest in
any award made to Tenant for loss of business or goodwill or for the taking of
Tenant's trade fixtures, the cost of relocating Tenant and/or disruption of
Tenant's business, if a separate award for such items is made to Tenant.

         16.      SURRENDER OF PREMISES; HOLDING OVER.

                  (a) No agreement to accept a surrender of the Premises shall
be valid unless it is in writing and signed by Landlord. At the end of the Term
or the termination of Tenant's right to possess the Premises, Tenant shall (1)
deliver to Landlord the Premises with all improvements located thereon in good
repair and condition, reasonable wear and tear (subject however to Tenant's
maintenance obligations) excepted, and with the HVAC System and hot water
equipment, light and light fixtures (including ballasts), and overhead doors and
related equipment in good working order, (2) deliver to Landlord all keys to the
Premises, and (3) remove all signage placed on the Premises, the Building or the
Land by or at Tenant's request. All fixtures, alterations, additions, and
improvements (whether temporary or permanent) shall be Landlord's property and
shall remain on the Premises except as provided in the next two sentences.
Provided that Tenant has performed all of its obligations hereunder, Tenant may
remove all unattached trade fixtures, furniture, and personal property placed in
the Premises by Tenant (but Tenant shall not remove any such item which was paid
for, in whole or in part, by Landlord). Additionally, Tenant shall remove such
alterations, additions, improvement, fixtures, equipment, wiring, furniture, and
other property as Landlord may request, provided such request is made within
fifteen (15) days after the end of the Term and provided that the installation
or construction of

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<PAGE>   10

the applicable alteration, improvement, additions, fixture or wiring was not
consented to by Landlord in writing (unless at the time of consent, Landlord
informed Tenant that such item would need to be removed upon expiration of the
Lease). All items not so removed shall, at the option of Landlord, be deemed
abandoned by Tenant and may be appropriated, sold, stored, destroyed, or
otherwise disposed of by Landlord without notice to Tenant and without any
obligation to account for such items and Tenant shall pay for the costs (if a
sale, after deducting proceeds of sale of such items) incurred by Landlord in
connection therewith. All work required of Tenant under this Section 16 (a.)
shall be coordinated with Landlord and be done in good and workmanlike manner,
in accordance with all Laws, and so as not to damage the Building or
unreasonably interfere with other tenants' use of their premises. Tenant shall,
at its expense, repair all damage caused by any work performed by Tenant under
this Section 16(a.)

                  (b) If Tenant fails to vacate the Premises at the end of the
Term, then Tenant shall be a Tenant at will and Tenant shall pay, in addition to
the other rent due hereunder, a daily base rental equal to 200% of the daily
Base Rent payable during the last month of the Term. Additionally, Tenant shall
defend, indemnify, and hold harmless Landlord from any damage, liability and
expense (including attorneys' fees and expenses) incurred because of such
holding over. No payments of money by Tenant to Landlord after the Term shall
reinstate, continue or extend the Term, and no extension of this Term shall be
valid unless it is in writing and signed by Landlord and Tenant.

         17. QUIET ENJOYMENT. Provided Tenant has fully performed its
obligations under this Lease, Tenant shall peaceably and quietly hold and enjoy
the Premises for the Term, without hindrance from Landlord or any party claiming
by, through, or under Landlord, but not otherwise.

         18. EVENTS OF DEFAULT. Each of the following events shall constitute an
"EVENT OF DEFAULT" under this Lease:

                  (a) Tenant fails to pay any rent when due or any payment or
reimbursement required under any other lease with Landlord when due, and in
either case such failure continues for a period of five days from the date
Landlord delivers written notice of such failure; provided, however, that
Landlord shall not be required to deliver written notice more than three (3)
times in any given 12 month period or more than six (6) times during the Term,
and subsequent to any such third notice in 12 months, or any such sixth notice
during the Term, any failure to pay rent or any other sum when due shall be an
immediate Event of Default without notice.

                  (b) The filing of a petition by or against Tenant or any
guarantor of Tenant's obligations hereunder (1) in any bankruptcy or other
insolvency proceeding; (2) seeking any relief under any debtor relief Law; (3)
for the appointment of a liquidator, receiver, trustee, custodian, or similar
official for all or substantially all of Tenant's property or for Tenant's
interest in this Lease; or (4) for reorganization or modification of Tenant's
capital structure (however, if any such petition is filed against Tenant, then
the filing of such petition shall not constitute an Event of Default, unless it
is not dismissed within sixty (60) days after the filing thereof).

                  (c) Tenants fails to discharge any lien placed upon the
Premises in violation of Section 22. within thirty (30) days after any such lien
or encumbrance is filed against the Premises.

                  (d) Tenant fails to comply with any term provision or covenant
of this Lease (other than those listed in Section 18. (a.), and such failure
continues for thirty (30) days after written notice thereof to Tenant.

         19.      REMEDIES.

                  (a) Upon any Event of Default, Landlord may, in addition to
all other rights and remedies afforded Landlord hereunder or by Law, take any of
the following actions:

                           (1) Terminate this Lease by giving Tenant written
notice thereof, in which event, Tenant shall
pay to Landlord the sum of (A) all rent accrued hereunder through the date of
termination, (B) all amounts due under Section 19. (b.), and (C) an amount equal
to (i) the total rent that Tenant would have been required to pay for the
remainder of the Term discounted to present value at a per annum rate equal to
the rate of interest set forth for 26-week U.S. governmental bills sold at a
discount from face value in units of $10,000 to $1,000,000 as published on the
date this Lease is terminated by The Wall Street Journal, Southwest Edition, in
its listing of "Money Rates" under the heading "Treasury Bills" (or, if no such
rate is published, the "Discount Rate" as published on such date under the
"Money Rates" listing), minus (ii) the then present fair rental value of the
Premises for such period, similarly discounted; or

                           (2) Terminate Tenant's right to possess the Premises
without terminating this Lease by giving
written notice thereof to Tenant, in which event Tenant shall pay to Landlord
(A) all rent and other amounts accrued hereunder to the date of termination of
possession, (B) all amounts due from time to time under Section 19 (b.), and (C)
all rent and other sums required hereunder to be paid by Tenant during the
remainder of the Term, diminished by any net sums thereafter received by
Landlord through reletting the Premises during such period; Landlord shall use
commercially reasonable efforts to mitigate Tenant's damages however, Landlord
shall not be obligated to relet the Premises and shall not be liable for, nor
shall Tenant's obligations hereunder be diminished because of, Landlord's
failure to relet the Premises or to collect rent due for a reletting. Tenant
shall not be entitled to the excess of any consideration obtained by reletting
over the rent due hereunder. Reentry by Landlord in the Premises shall not
affect Tenant's obligations hereunder for the unexpired Term; rather, Landlord
may, from time to time, bring action against Tenant to collect amounts

                                        7

<PAGE>   11

due by Tenant, without the necessity of Landlord's waiting until the expiration
of the Term. Unless Landlord delivers written notice to Tenant expressly stating
that it has elected to terminate this Lease, all actions taken by Landlord to
exclude or dispossess Tenant of the Premises shall be deemed to be taken under
this Section 19(a)(2). If Landlord elects to proceed under this Section
19(a)(2), it may at any time elect to terminate this Lease under Section 19 (a)
(1).

Additionally, after written notice of a default which remains uncured for more
than 30 days, Landlord may alter locks or other security devices at the Premises
to deprive Tenant of access thereto, and Landlord shall not be required to
provide a new key or right of access to Tenant.

                  (b) Tenant shall pay to Landlord all direct reasonable costs
incurred by Landlord (including court costs and reasonable attorneys' fees and
expenses) in (1) obtaining possession of the Premises, (2) removing and storing
Tenant's or any other occupant's property, (3) repairing, restoring, altering,
remodeling, or otherwise putting the Premises into condition acceptable to a new
tenant, (4) if Tenant is dispossessed of the Premises and this Lease is not
terminated, reletting all or any part of the Premises (including brokerage
commissions, cost of tenant finish work, and other costs incidental to such
reletting), (5) performing Tenant's obligations which Tenant failed to perform,
and (6) enforcing, or advising Landlord of, its rights, remedies, and recourses.
Landlord's acceptance of rent following an Event of Default shall not waive
Landlord's rights regarding such Event of Default. Landlord's receipt of rent
with knowledge of any default by Tenant hereunder shall not be a waiver of such
default, and no waiver by Landlord of any provision of this Lease shall be
deemed to have been made unless set forth in writing and signed by Landlord. No
waiver by Landlord of any violation or breach of any of the terms contained
herein shall waive Landlord's rights regarding any future violation of such term
or violation of any other term. If Landlord repossesses the Premises pursuant to
the authority herein granted, then Landlord shall have the right to (A) keep in
place and use or (B) remove and store, at Tenant's expense, all of the
furniture, fixtures, equipment and other property in the Premises, including
that which is owned by or leased to Tenant at all times before any foreclosure
thereon by Landlord or repossession thereof by any lessor thereof or third party
having a lien thereon. Landlord may relinquish possession of all or any portion
of such furniture, fixtures, equipment and other property to any person (a
"CLAIMANT") who presents to Landlord a copy of any instrument represented by
Claimant to have been executed by Tenant (or any predecessor of Tenant) granting
Claimant the right under various circumstances to take possession of such
furniture, fixtures, equipment or other property; provided Landlord is
reasonable in believing that the instrument is authentic and legal. Landlord
may, at its option and without prejudice to or waiver of any rights it may have,
(i) escort Tenant to the Premises to retrieve any personal belongings of Tenant
and/or its employees not covered by the Landlord's statutory lien or (ii) obtain
a list from Tenant of the personal property of Tenant and/or its employees that
is not covered by the Landlord's statutory lien and make such property available
to Tenant and/or Tenant's employees; however, Tenant first shall pay in cash all
costs and estimated expenses to be incurred in connection with the removal of
such property and making it available. The rights of Landlord herein stated are
in addition to any and all other rights that Landlord has or may hereafter have
at law or in equity, and Tenant agrees that the rights herein granted Landlord
are commercially reasonable.

         20. LANDLORD'S DEFAULT. If Landlord fails to perform any of its
obligations hereunder within 30 days after written notice from Tenant specifying
such failure, Tenant's exclusive remedy shall be an action for damages. Unless
Landlord fails to so cure such default after such notice, Tenant shall not have
any remedy or cause of action by reason thereof. Except for gross negligence or
willful misconduct, Liability of Landlord to Tenant for any default by Landlord,
shall be limited to actual, direct, but not consequential, damages therefor and
shall be recoverable only from the interest of Landlord in the Building and the
Land, and neither Landlord nor Landlord's owners shall have any personal
liability therefor.

         21.      MORTGAGES.

                  (a) This Lease shall be subordinate to any deed of trust,
mortgage or other security instrument (a "MORTGAGE"), and any ground lease,
master lease, or primary lease (a "PRIMARY LEASE") that now or hereafter covers
any portion of the Premises (the mortgagee under any Mortgage or the lessor
under any Primary Lease is referred to herein as "LANDLORD'S MORTGAGEE"), and to
increases, renewals, modifications, consolidations, replacements, and extensions
thereof. However, any Landlord's Mortgagee may elect to subordinate its Mortgage
or Primary Lease (as the case may be) to this Lease by delivering written notice
thereof to Tenant. The provisions of this Section 21. shall be self-operative,
and no further instrument shall be required to effect such subordination;
however, Landlord shall deliver to Tenant, and Tenant shall execute from time to
time within ten days after delivery thereof to Tenant, an instrument from each
Landlord's Mortgagee evidencing the subordination of this Lease to any such
Mortgage or Primary Lease (which instrument shall include a non-disturbance
provision in favor of Tenant and shall be on Landlord's Mortgagee's standard
form).

                  (b) Tenant shall attorn to any party succeeding to Landlord's
interest in the Premises, whether by purchase, foreclosure, deed in lieu of
foreclosure, power of sale, termination of lease, or otherwise, upon such
party's request, and shall execute such agreements confirming such attornment as
such party may reasonably request. Tenant shall not seek to enforce any remedy
it may have for any default on the part of Landlord without first giving written
notice by certified mail, return receipt requested, specifying the default in
reasonable detail to any Landlord's Mortgagee whose address has been given to
Tenant, and affording such Landlord's Mortgagee a reasonable opportunity to
perform Landlord's obligations hereunder.

                  (c)      Notwithstanding any such attornment or subordination
of a Mortgage or Primary Lease to

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<PAGE>   12

this Lease, the Landlord's Mortgagee shall not be liable for any acts of any
previous landlord, shall not be obligated to install the Shell or Initial
Improvements, and shall not be bound by any amendment to which it did not
consent in writing nor any payment of rent made more than one month in advance.

         22. ENCUMBRANCES. Tenant has no authority, express or implied, to
create or place any lien or encumbrance of any kind or nature whatsoever upon,
or in any manner to bind Landlord's property or the interest of Landlord or
Tenant in the Premises or to charge the rent for any claim in favor of any
person dealing with Tenant, including those who may furnish materials or perform
labor for any construction or repairs. Tenant shall pay or cause to be paid all
sums due for any labor performed or materials furnished in connection with any
work performed on the Premises by or at the request of Tenant. Tenant shall give
Landlord immediate written notice of the placing of any lien or encumbrance
against the Premises.

         23.      MISCELLANEOUS.

                  (a) Words of any gender used in this Lease shall include any
other gender, and words in the singular shall include the plural, unless the
context otherwise requires. The captions inserted in this Lease are for
convenience only and in no way affect the interpretation of this Lease. The
following terms shall have the following meanings: "LAWS" shall mean all
federal, state, and local laws, rules, and regulations; all court orders,
governmental directives, and governmental orders; and all restrictive covenants
affecting the Property, and "LAW" shall mean any of the foregoing; "AFFILIATE"
shall mean any person or entity which, directly or indirectly, controls, is
controlled by, or is under common control with the party in question; "TENANT
PARTY" shall include Tenant, any assignees claiming by, through, or under
Tenant, any subtenants claiming by, through or under Tenant, and any of their
respective agents, contractors, employees, and invitees; and "INCLUDING" shall
mean including, without limitation. The normal rule of construction that any
ambiguities be resolved against the drafting party shall not apply to the
interpretation of this Lease or any exhibits or amendments hereto.

                  (b) Landlord may transfer and assign, in whole or in part, its
rights and obligations in the Building and property that are the subject to this
Lease, in which case Landlord shall have no further liability hereunder, except
for events occurring during the term of its ownership. Each party shall furnish
to the other, promptly upon demand, a corporate resolution, proof of due
authorization by partners, or other appropriate documentation evidencing the due
authorization of such party to enter into this Lease.

                  (c) Whenever a period of time is herein prescribed for action
to be taken by Landlord, Landlord shall not be liable or responsible for, and
there shall be excluded from the computation for any such period of time, any
delays due to strikes, riots, acts of God, shortages of labor materials, war,
governmental laws, regulations, or restrictions, or any other causes of any kind
whatsoever which are beyond the control of Landlord.

                  (d) Tenant shall, from time to time, within ten days after
request of Landlord, deliver to Landlord, or Landlord's designee, a certificate
of occupancy for the Premises, financial statements for itself and any guarantor
of its obligations hereunder, evidence reasonably satisfactory to Landlord that
Tenant has performed its obligations under this Lease (including evidence of the
payment of the Security Deposit), and an estoppel certificate stating that this
Lease is in full effect, the date to which rent has been paid, the unexpired
Term and such other factual matters pertaining to this Lease as may be requested
by Landlord. Tenant's obligation to furnish the above-described items in a
timely fashion is a material inducement for Landlord's execution of this Lease.

                  (e) This Lease constitutes the entire agreement of the
Landlord and Tenant with respect to the subject matter of this Lease, and
contains all of the covenants and agreements of Landlord and Tenant with respect
thereto. Landlord and Tenant each acknowledge that no representations,
inducements, promises or agreements, oral or written, have been made by Landlord
or Tenant, or anyone acting on behalf of Landlord or Tenant, which are not
contained herein, and any prior agreements, promises, negotiations, or
representations not expressly set forth in this Lease are of no effect. This
Lease may not be altered, changed or amended except by an instrument in writing
signed by both parties hereto.

                  (f) All obligations of Tenant hereunder not fully performed by
the end of the Term shall survive, including, without limitation, all payment
obligations with respect to Taxes and insurance and all obligations concerning
the condition and repair of the Premises. Upon the end of the Term and before
Tenant vacates the Premises, Tenant shall pay to Landlord any amount reasonably
estimated by Landlord as necessary to put the Premises in good condition and
repair, reasonable wear and tear excluded. Tenant shall also, prior to vacating
the Premises, pay to Landlord the amount, as estimated by Landlord, of Tenant's
obligation hereunder for Operating Expenses for the year in which the Term ends.
All such amounts shall be used and held by Landlord for payment of such
obligations of Tenant hereunder, with Tenant being liable for any additional
costs therefor upon demand by Landlord or with any excess to be returned to
Tenant after all such obligations have been determined and satisfied as the case
may be. Any Security Deposit held by Landlord may be credited against the amount
due by Tenant under this Section 23(f).

                  (g) If any provision of this Lease is illegal, invalid or
unenforceable, then the remainder of this Lease shall not be affected thereby,
and in lieu of each such provision, there shall be added, as a part of this
Lease, a provision as similar in terms to such illegal, invalid or unenforceable
clause or provision as may be possible and be legal, valid and enforceable.

                  (h) All references in this Lease to the date hereof, or
similar references shall be deemed to refer

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<PAGE>   13

to the last date, in point of time, on which all parties hereto have executed
this Lease.

         (i) Landlord and Tenant each warrant to the other that it has not dealt
with any broker or agent in connection with this Lease, other than Hill
Partners, Inc. and C.B. Richard Ellis (the "Brokers"). Tenant and Landlord shall
each indemnify the other against all costs, attorneys' fees, and other
liabilities for commissions or other compensation claimed by any broker or agent
(other than the named Brokers) claiming the same by, through, or under the
indemnifying party. Landlord shall pay commission to such Brokers pursuant to
separate agreements.

         (j) If and when included within the term "Tenant" as used in this
instrument, there is more than one person, firm or corporation, all shall
jointly arrange among themselves for their joint execution of a notice
specifying an individual at a specific address within the continental United
States for the receipt of notices and payments to Tenant. All parties included
within the terms Landlord and Tenant, respectively, shall be bound by notices
given in accordance with the provisions of Section 24 to the same effect as if
each had received such notice.

         (k) The terms and conditions of this Lease are confidential and Tenant
shall not disclose the terms of this Lease to any third party except as may be
required by law or its auditors or to enforce its rights hereunder.

         (l) Tenant shall pay interest on all past-due rent from the date due
until paid at the maximum lawful rate. In no event, however, shall the charges
permitted under this Section 23(l) or elsewhere in this Lease, to the extent
they are considered to be interest under applicable Law, exceed the maximum
lawful rate of interest.

         24. NOTICES. Each provision of this instrument or of any applicable
Laws and other requirements with reference to the sending, mailing or delivering
of notice or the making of any payment hereunder shall be deemed to be complied
with when and if the following steps are taken:

                  (a) All rent shall be payable to Landlord at the address for
Landlord set forth below or at such other address as Landlord may specify from
time to time by written notice delivered in accordance herewith. Tenant's
obligation to pay rent shall not be deemed satisfied until such rent has been
actually received by Landlord.

                  (b) All payments required to be made by Landlord to Tenant
hereunder shall be payable to Tenant at the address set forth below, or at such
other address within the continental United States as Tenant may specify from
time to time by written notice delivered in accordance herewith.

                  (c) Any written notice or document required or permitted to be
delivered hereunder shall be deemed to be delivered upon the earlier to occur of
(1) tender of delivery (in the case of a hand-delivered notice), (2) deposit in
the United States Mail, postage prepaid, Certified Mail or (3) receipt by
facsimile transmission, in each case, addressed to the parties hereto at the
respective addresses set out below, or at such other address as they have
theretofore

                                       10

<PAGE>   14

specified by written notice delivered in accordance herewith. If Landlord has
attempted to deliver notice to Tenant at Tenant's address reflected on
Landlord's books but such notice was returned or acceptance thereof was refused,
then Landlord may post such notice in or on the premises, which notice shall be
deemed delivered to Tenant upon the posting thereof.

         25.      HAZARDOUS WASTE.  The term "HAZARDOUS SUBSTANCES," as used in
this Lease shall mean pollutants, contaminants, toxic or hazardous wastes, or
any other substances, the removal of which is required or the use of which is
restricted, prohibited or penalized by any "ENVIRONMENTAL LAW," which term shall
mean any Law relating to health, pollution, or protection of the environment.
Tenant hereby agrees that (a) no activity will be conducted on the Premises that
will produce any Hazardous Substances, except for such activities that are part
of the ordinary course of Tenant's business activities (the "PERMITTED
ACTIVITIES") provided such Permitted Activities are conducted in accordance with
all Environmental Laws and have been approved in advance in writing by Landlord;
(b) the Premises will not be used in any manner for the storage of any Hazardous
Substances except for any temporary storage of such materials that are used in
the ordinary course of Tenant's business (the "PERMITTED MATERIALS") provided
such Permitted Materials are properly stored in a manner and location satisfying
all Environmental Laws and approved in advance in writing by Landlord; (c) no
portion of the Premises will be used as a landfill or a dump; (d) Tenant will
not install any underground tanks of any type; (e) Tenant will not allow any
surface or subsurface conditions to exist or come into existence that
constitute, or with the passage of time may constitute a public or private
nuisance; (f) Tenant will not permit any Hazardous Substances to be brought onto
the premises, except for the Permitted Materials, and if so brought or found
located thereon, the same shall be immediately removed by Tenant, with proper
disposal, and all required cleanup procedures shall be diligently undertaken
pursuant to all Environmental Laws; (g) Tenant will maintain on the Premises a
list of all materials stored at the Premises for which a material safety data
sheet (an "MSDS") was issued by the producers or manufacturers thereof, together
with copies of the MSDS' s for such materials, and shall deliver such list and
MSDS copies of Landlord upon Landlord's request therefor; and (h) Tenant shall
remove all Permitted Materials from the Premises in a manner acceptable to
Landlord before Tenant's right to possess the Premises is terminated. If at any
time during or after the Term, the Premises are found to be so contaminated or
subject to such conditions, Tenant shall defend, indemnify and hold Landlord
harmless from all claims, demands, actions, liabilities, costs, expenses,
damages and obligations of any nature arising from or as a result of the use of
the Premises by Tenant. Unless expressly identified on an addendum to this
Lease, as of the date hereof there are no Permitted Activities or Permitted
Materials for purposes of the foregoing provisions and none shall exist unless
and until approved in writing by the Landlord. Landlord may enter the Premises
and conduct environmental inspections and tests therein as it may reasonably
require from time to time provided that Landlord shall use reasonable efforts to
minimize the interference with Tenant's business. Such inspections and tests
shall be conducted at Landlord's expense, unless they reveal the presence of
Hazardous Substances (other than Permitted Materials) or that Tenant has

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<PAGE>   15

not complied with the requirements set forth in this Section 25, in which case
Tenant shall reimburse Landlord for the cost thereof within ten days after
Landlord's request thereof.

         TENANT ACKNOWLEDGES THAT UPON OCCUPANCY OF THE PREMISES EXCEPT FOR
WRITTEN PUNCH LIST ITEMS (1) IT HAS INSPECTED AND ACCEPTS THE PREMISES IN AN ?AS
IS, WHERE IS? CONDITION, (2) THE BUILDING'S IMPROVEMENTS ARE SUITABLE FOR THE
PURPOSE FOR WHICH THE PREMISES ARE LEASED AND LANDLORD HAS MADE NO WARRANTY,
REPRESENTATION, COVENANT, OR AGREEMENT WITH RESPECT TO THE MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR PURPOSE OF THE PREMISES, (3) THE PREMISES ARE IN GOOD
AND SATISFACTORY CONDITION, (4) NO REPRESENTATIONS AS TO THE REPAIR OF THE
PREMISES, NOR PROMISES TO ALTER, REMODEL OR IMPROVE THE PREMISES HAVE BEEN MADE
BY LANDLORD (UNLESS AND EXCEPT AS MAY BE SET FORTH IN EXHIBIT B ATTACHED TO THIS
LEASE, OR AS IS OTHERWISE EXPRESSLY SET FORTH IN THIS LEASE), AND (5) THERE ARE
NO REPRESENTATIONS OR WARRANTIES, EXPRESSED, IMPLIED OR STATUTORY, EXCEPT AS
PROVIDED HEREIN.

         Executed by Landlord on the 1 day of OCT, 1998.

                                 LANDLORD:
                                 KRAMER 34 HP, LTD.
                                 By: 2800 Industrial, Inc., general partner

                                 By:      /s/ R. E. Anderson
                                          -------------------------------------
                                          Richard Anderson
                                          Vice President
                          Address: c/o Hill Partners, Inc.
                                         2800 Industrial Terrace
                                         Austin, Texas 78758
                        Telephone: (512) 835-4455
                              Fax: (512) 835-1222

                                 TENANT:
                                 IXC COMMUNICATIONS SERVICES, INC.

                                 By:      /s/ Stuart K. Coppens
                                          -------------------------------------
                                          Stuart K. Coppens
                                          VP
                          Address: 1122 Capital of Texas Hwy, S
                                          Austin, TX 78746
                        Telephone: (512) 427-3757
                              Fax: (512) 329-8638

EXHIBIT "A"       Description of Premises
EXHIBIT "A-1"     Floor Plan
EXHIBIT "A-2"     Description of Project
EXHIBIT "B"            Tenant Finish-Work:  Allowance       Approved as to form
EXHIBIT "C"            Expansion Space                          Legal dept.
EXHIBIT "D"       Extension Option
EXHIBIT "E"            Guaranty

                                       12

<PAGE>   16

                                    EXHIBIT A

                                LEGAL DESCRIPTION

BUILDING:                       Kramer 3

LEGAL DESCRIPTION:              Lot 3, BRAKER CENTER
                                IV, a subdivision in Travis County,
                                Texas, according to the map or plat
                                of record in Volume 101, Page 1,
                                Plat Records of Travis County,
                                Texas.

ADDRESS:                        1825-A Kramer Lane
                                Austin, Texas  78758

(DIAGRAM)

                                       13

<PAGE>   17

                                   EXHIBIT A-1

(DIAGRAM)

                                       14

<PAGE>   18

                                   EXHIBIT A-1

(DIAGRAM)

                                       15

<PAGE>   19

                                    EXHIBIT B

                          TENANT FINISH-WORK: ALLOWANCE

         1. Landlord, at its sole cost and expense, shall complete construction
of the shell of the Building including the roof, slab, exterior walls and site
work (the "SHELL IMPROVEMENTS"). All such construction shall be completed by
Landlord in a good and workmanlike manner and in accordance with all applicable
laws and regulations.

         2. Before the commencement of interior construction the Tenant, at its
sole cost and expense, shall provide to Landlord for its approval final working
drawings, prepared by an architect that has been approved by Landlord (which
approval shall not be unreasonably withheld), of all improvements that Tenant
proposes to install in the Premises; such working drawings shall include the
partition layout, ceiling plan, electrical outlets and switches, telephone
outlets, HVAC, mechanical and plumbing systems of the Building, and detailed
plans and specifications for the construction of the improvements called for
under this Exhibit in accordance with all applicable governmental laws, codes,
rules, and regulations. Landlord's approval of such working drawings shall not
be unreasonably withheld or delayed, provided that (a) they comply with all
applicable governmental laws, codes, rules, and regulations, (b) such working
drawings are sufficiently detailed to allow construction of the improvements in
a good and workmanlike manner, (c) the improvements depicted thereon conform to
the rules and regulations promulgated from time to time by the Landlord for the
construction of tenant improvements (a copy of which has been delivered to
Tenant), and (d) the materials used are building standard (including doors,
ceiling tiles, lights and occupancy sensors). As used herein, "WORKING DRAWINGS"
shall mean the final working drawings approved by Landlord, as amended from time
to time by any approved changes thereto, and "INITIAL IMPROVEMENTS" shall mean
all improvements to be constructed in accordance with and as indicated on the
Working Drawings. Approval by Landlord of the Working Drawings shall not be a
representation or warranty of Landlord that such drawings are adequate for any
use, purpose, or condition, or that such drawings comply with any applicable law
or code, but shall merely be the consent of Landlord to the performance of the
Initial Improvements. Tenant shall, at Landlord's request, sign the Working
Drawings to evidence its review and approval thereof. All changes in the Initial
Improvements must receive the prior written approval of Landlord and upon
completion of the Initial Improvements, Tenant shall furnish Landlord with an
accurate, reproducible "as-built" plan (e.g., sepia) and a CADD disk of the
improvements as constructed, which plan shall be incorporated into this Lease by
this reference for all purposes.

         3. Upon substantial completion of the Shell Improvements by Landlord,
Tenant shall be responsible for constructing and installing the Initial
Improvements. Tenant agrees to file for all required building and signage
permits necessary for the construction of the Initial Improvements and to use
good faith and diligent efforts to obtain all such permits. The cost of the
pursuit of such permits shall be borne by Tenant; however, Landlord will provide
its cooperation in connection therewith and, if necessary, shall join in such
applications, and execute such other documents, as Tenant may reasonably request
for such purposes. The Initial Improvements shall be diligently performed by
contractors and subcontractors reasonably acceptable to Landlord in a good and
workmanlike manner that is free of defects and is in strict conformance with the
Working Drawings and all applicable governmental laws, codes, rules, and
regulations. Tenant and its contractors and subcontractors shall be required to
maintain such liability and builder's risk insurance during construction of the
Initial Improvements as is reasonably required by Landlord.

         4. If completion of the Initial Improvements is delayed beyond November
15, 1998 for any reason other than Landlord's failure to substantially complete
construction of the Shell Improvements on or before October 15, 1998, then,
notwithstanding any provision to the contrary in this Lease, Tenant's obligation
to pay Basic Rent and Tenant's Proportionate Share of Operating Expenses
hereunder shall commence on November 15, 1998. If the Premises are not ready for
occupancy and the Initial Improvements are not substantially completed (as
reasonably determined by Landlord) on November 15, 1998 due to Landlord's
failure to timely complete the Shell Improvements, then the Commencement Date
shall be sixty (60) days after Landlord delivers the Premises in Shell
Condition.

         5. Landlord shall provide to Tenant a construction allowance (the
"CONSTRUCTION ALLOWANCE") equal to the lesser of (a) $20.00 per usable square
foot in that portion of the Premises initially delivered to Tenant or (b) the
Total Construction Costs, as adjusted for any approved changes to the Initial
Improvements.

         6. Tenant shall bear the entire cost of constructing the Initial
Improvements (including, without limitation, costs of design, engineering,
construction, labor and materials, additional janitorial services, related taxes
and insurance costs, all of which costs are herein collectively called the
"TOTAL CONSTRUCTION COSTS") in excess of the Construction Allowance. Landlord
shall advance the Construction Allowance at such time as Tenant has furnished to
Landlord a certificate of occupancy for the Premises, lien waivers) from
Tenant's general contractor(s) establishing that all bills for labor and
materials incorporated in the Initial Improvements have been paid, and a
certificate from Tenant's architect certifying that the Initial Improvements
have been completed in accordance with the Working Drawings. Notwithstanding the
foregoing, at Tenant's request Landlord will fund portions of the Construction
Allowance monthly (on the 25th day of each month) for portions of the Initial
Improvements actually completed during the previous month, so long as Tenant
delivers to Landlord on or before the 10th day of the month a draw request along
with lien waivers from all contractors and subcontractors and a certificate from
the Tenant's architect's stating that the requested funds are for improvements
which have been incorporated into the Premises in accordance with the Working
Drawings. In no event shall Landlord be required to reimburse Tenant for costs
in excess of the Construction Allowance, as such excess costs will remain the
sole responsibility of Tenant. Furthermore, Landlord shall have no obligation to
reimburse Tenant for any the fees of any architect, engineer or other consultant
which are not reasonable and customary. All of the Initial Improvements will
become and shall remain Landlord's property on and after its construction or
installation on the Premises.

                                       16

<PAGE>   20

         7. Landlord or its affiliate shall have the right to inspect and
supervise the Work, and to ensure the Work does not adversely affect the
Building, and the Building's systems.

                                       17

<PAGE>   21

                                [Expansion Space]

         Beginning on the first day of the thirteenth (13th) month of the term
(the "EXPANSION DATE"), Tenant shall lease for the remaining Term 37,485
additional square feet of rentable area in the Building, constituting the
remainder of the Building (the "EXPANSION SPACE").

         Landlord shall cause the Expansion Space to be in shell condition and
made ready for Tenant's occupancy sixty (60) days prior to the Expansion Date,
in accordance with the procedures referenced in Exhibit B. The Allowance
applicable to the Expansion Space shall be a sum equal to $16.00 per rentable
square foot in the Expansion Space. Except as set forth in this Exhibit C, all
Expansion Space taken by Tenant shall be taken "as is" and Landlord shall have
no obligation to construct any leasehold improvements therein or to make any
alterations thereto.

         Tenant shall be required to commence paying rent on such Expansion
Space upon the date that is the sooner to occur of (a) the date that Tenant
commences to occupy such space or (b) sixty (60) days after Landlord delivers
the Premises in shell condition but in no event prior to the Expansion Date. If
the Expansion Space is not in shell condition sixty (60) days prior to the
Expansion Date, Landlord shall not be liable for damages therefor and Tenant
shall accept possession of the Expansion Space when Landlord tenders possession
thereof to Tenant in shell condition and Tenant's obligation to pay Base Rent
and Operating Expenses under Section 2.(b) of this Lease with respect to such
Expansion Space shall commence when Landlord tenders possession of such
Expansion Space to Tenant in shell condition.

         Except as provided in this Exhibit C, the leasing of the Expansion
Space shall be upon the same terms and conditions as the leasing of the initial
Premises and shall be upon and subject to all of the provisions of this Lease.
Upon the Expansion Date: (i) the Base Rent payable by Tenant shall be increased
by the number of square feet contained within the Expansion Space multiplied by
the dollar amount per square foot provided in Section 2(a) of this Lease, (ii)
the "Premises" (as defined in the Lease) shall be deemed to include the
Expansion Space, and (iii) Tenant's Proportionate share shall be increased
commensurately to reflect the addition of the Expansion Space to the Premises.
It being acknowledged that on the Expansion Date, Tenant will be leasing the
entire Building and therefore its Proportionate Share of Operating Expenses
shall be 100%.

         Notwithstanding anything to the contrary contained herein, Landlord
shall have the right to lease any portion of the Expansion Space to another
tenant or allow another party to use or occupy the Expansion Space, so long as
such lease or occupancy right is terminable on 30 days notice and expires sixty
(60) days prior to the Expansion Date.

                                       18

<PAGE>   22

                                EXTENSION OPTION

         Provided no Event of Default exists and Tenant is occupying the entire
Premises at the time of such election, Tenant may renew this Lease for one (1)
additional period of five (5) years on the same terms provided in this Lease
(except as set forth below), by delivering written notice of the exercise
thereof to Landlord not later than one hundred eighty (180) days before the
expiration of the Term. On or before the commencement date of the extended Term,
Landlord and Tenant shall execute an amendment to this Lease extending the Term
on the same terms provided in this Lease, except as follows:

                  (a) The Base Rent payable for each month during each such
         extended Term shall be the prevailing rental rate in the Project, at
         the commencement of such extended Term, for space of equivalent
         quality, size, utility and location, with the length of the extended
         Term and the credit standing of Tenant to be taken into account;

                  (b) Tenant shall have no further renewal options unless
expressly granted by Landlord in writing; and

                  (c) Landlord shall lease to Tenant the Premises in their
         then-current condition, except that Tenant shall be entitled to an
         improvement allowance equal to the prevailing rate in the Project, at
         the commencement of such extended Term, for space of equivalent
         quality, size, utility and location, with the length of the extended
         Term to be taken into account.

         Tenant's rights under this Exhibit shall terminate if (1) this Lease or
Tenant's right to possession of the Premises is terminated, (2) Tenant assigns
any of its interest in this Lease or sublets any portion of the Premises, or (3)
Tenant fails to timely exercise its option under this Exhibit, time being of the
essence with respect to Tenant's exercise thereof.

                                       19

<PAGE>   23

                       FIRST AMENDMENT TO LEASE AGREEMENT

         THIS FIRST AMENDMENT TO LEASE AGREEMENT is made and entered as of the
29 day of December 1998, by and between IXC COMMUNICATIONS SERVICES, INC.
("Tenant"), and KRAMER 34, HP, LTD. ("Landlord").

                                    RECITALS

         A. Pursuant to a Lease Agreement dated October 1, 1998 (the "Lease"),
Landlord leased to Tenant certain space in the building commonly known as
"Kramer 3" in Austin, Texas, as more fully described in the Lease.

         B. Landlord and Tenant desire to amend the Lease as hereinafter
provided.

                                    AMENDMENT

         In consideration of the premises, the mutual covenants and agreements
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant hereby amend
the Lease as follows:

         1. Notwithstanding anything to the contrary contained in Section 1(a)
of the Lease, it is hereby agreed that the initial size of the Premises is
24,833 and Tenant's initial Proportionate Share is 39.95%.

         2. Section 1(b) of the Lease is hereby deleted in its entirety and
replaced by the following:

         (b) The lease term shall be sixty (60) months, beginning on the later
         of (i) sixty (60) days after the date of substantial completion of the
         Shell Improvements (as defined on Exhibit B) or (ii) January 1, 1999
         (the "COMMENCEMENT DATE"), and ending December 31, 2003 (the "TERM",
         which defined term shall include all renewals and extensions of the
         Term, if any). Notwithstanding the foregoing if the Commencement Date
         does not occur on January 1, 1999, then the Term shall end sixty (60)
         months after the first day of the first full calendar month after the
         Commencement Date.

         3. The last sentence of Section 2(b) of the Lease is hereby deleted in
its entirety and replaced by the following:

         The amounts of the initial monthly Base Rent and Tenant's Proportionate
         Share of Operating Expenses (and the part thereof attributable to
         Taxes) are as follows:

<TABLE>

<S>                                                                 <C>
         Base Rent (Section 2.(a))                                  $ 20,363.06
         Operating Expenses, excluding Taxes (Section 2(b))         $  1,999.24
         Taxes (Sections 2.(b) and 3.(a))                           $  2,438.58

         Total initial monthly payment                              $ 24,800.88
                                                                    ===========
</TABLE>

                                        1

<PAGE>   24

         4. In the second and third lines of the last paragraph of the Lease
(right before the signature blocks), the two (2) question marks are hereby
replaced by two (2) quotation marks. Further "Exhibit 'E' Guaranty" is hereby
deleted from the list of exhibits on the last page of the Lease.

         5. Exhibit A-1 to the Lease is hereby replaced in its entirety by
EXHIBIT "A-1" attached hereto.

         6. Each reference to the date "November 15, 1998" in paragraph 4 of
Exhibit B to the Lease is hereby replaced by "January 1, 1999".

         7. The first sentence of Exhibit C to the Lease is hereby deleted in
its entirety and replaced by the following:

         Beginning on January 1, 2000 (the "EXPANSION DATE"), Tenant shall lease
         for the remaining Term 37,334 additional square feet of rentable area
         in the Building, constituting the reminder of the Building (the
         "EXPANSION SPACE").

         8. EXHIBIT D attached hereto is hereby added to the Lease as Exhibit D
thereto.

         9. Except as defined differently herein or the context clearly requires
otherwise, all capitalized terms used in this Amendment shall have the meanings
ascribed to them under the Lease. Except as expressly amended hereby, the Lease
shall remain unchanged and in full force and effect, and is hereby ratified by
Landlord and Tenant.

         EXECUTED as of the date first written above.

                          TENANT:

                          IXC COMMUNICATIONS SERVICES, INC.

                          By:        /s/ Stuart K. Coppens
                                     -------------------------------------
                          Name:      STUART K. COPPENS
                          Title:     VP

                          LANDLORD:

                          KRAMER 34 HP, LTD.

                          By:        2800 Industrial Inc., General Partner

                                     By:    /s/ Richard E. Anderson
                                            -----------------------------------
                                            Richard E. Anderson
                                            Vice President

                                        2

<PAGE>   25

                                    EXHIBIT D

                                EXTENSION OPTION

         Provided no Event of Default exists and Tenant is occupying the entire
Premises at the time of such election, Tenant may renew this Lease for one (1)
additional period of five (5) years on the same terms provided in this Lease
(except as set forth below), by delivering written notice of the exercise
thereof to Landlord not later than one hundred eighty (180) days before the
expiration of the Term. On or before the commencement date of the extended Term,
Landlord and Tenant shall execute an amendment to this Lease extending the Term
on the same terms provided in this Lease, except as follows:

                  (a) The Base Rent payable for each month during each such
extended Term shall be the prevailing rental rate in the Project, at the
commencement of such extended Term, for space of equivalent quality, size,
utility and location, with the length of the extended Term and the credit
standing of Tenant to be taken into account;

                  (b) Tenant shall have no further renewal options unless
expressly granted by Landlord in writing; and

                  (c) Landlord shall lease to Tenant the Premises in their
then-current condition, except that Tenant shall be entitled to an improvement
allowance equal to the prevailing rate in the Project, at the commencement of
such extended Term, for space of equivalent quality, size, utility and location,
with the length of the extended Term to be taken into account.

         Tenant's right under this Exhibit shall terminate if (1) this Lease or
Tenant's right to possession of the Premises is terminated, (2) Tenant assigns
any of its interest in this Lease or sublets any portion of the Premises, or (3)
Tenant fails to timely exercise its option under this Exhibit, time being of the
essence with respect to Tenant's exercise thereof.

                                        3

<PAGE>   26

                                    EXHIBIT A

                                    (DIAGRAM)

                                        4

<PAGE>   27

                       SECOND AMENDMENT TO LEASE AGREEMENT

THIS SECOND AMENDMENT TO LEASE AGREEMENT is made and entered as of the 13th day
of May 1999, by and between IXC COMMUNICATIONS SERVICES, INC. ("Tenant") and
KRAMER 34 HP, LTD. ("Landlord").

                                    RECITALS

         A. Pursuant to a Lease Agreement dated October 1, 1998 (as amended by
First Amendment to Lease Agreement, the "Lease"), Landlord leased to Tenant
certain space in the building commonly known as "Kramer 3" in Austin, Texas, as
more fully described in the Lease.

         B. Contemporaneously herewith, Landlord has leased to Tenant certain
space in an adjacent building commonly known as "Kramer 2" pursuant to a Lease
Agreement dated of even date herewith (the "Building 2 Lease").

         C. Landlord and Tenant desire to extend the Term of the Lease to be
coterminous with the Building 2 Lease and otherwise amend the Lease as
hereinafter provided.

                                    AMENDMENT

         In consideration of the premises, the mutual covenants and agreements
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant hereby amend
the Lease as follows:

         1. Notwithstanding anything to the contrary contained in the Lease, it
is hereby agreed that the initial Term shall be extended to be coterminous with
the initial term of the Building 2 Lease. Section 1(b) of the Building 2 Lease
(describing the term of the Building 2 Lease) is reprinted below for reference:

         The Lease term shall be seventy two (72) months, beginning on the later
         of (i) sixty (60) days after substantial completion of the Shell
         Improvements (as defined on Exhibit B) or (ii) August 1, 1999 (the
         "COMMENCEMENT DATE"), and ending July 31, 2005 (the "TERM", which
         defined term shall include all renewals and extensions of the Term, if
         any). Notwithstanding the foregoing if the Commencement Date does not
         occur on August 1, 1999, then the Term shall end seventy-two (72)
         months after the first day of the first full calendar month after the
         Commencement Date.

         2. The monthly Base Rent payable during the extension of the initial
Term (as provided in paragraph 1 above) shall be $.86 per square foot of the
Premises.

         3. Exhibit C to the Lease is hereby deleted in its entirety and
replaced by Exhibit "C" attached hereto.

                                        1

<PAGE>   28

         4. Except as defined differently herein or the context clearly requires
otherwise, all capitalized terms used in this Amendment shall have the meanings
ascribed to them under the Lease. Except as expressly amended hereby, the Lease
shall remain unchanged and in full force and effect, and is hereby ratified by
Landlord and Tenant.

         EXECUTED as of the date first written above.

                             TENANT:

                             IXC COMMUNICATIONS SERVICES, INC.

                                               Approved as to form
                                                   Legal dept.

                            By:          /s/  Stuart K. Coppens
                                        -------------------------------------
                            Name:        Stuart K. Coppens
                            Title:       VP

                             LANDLORD:

                             KRAMER 34 HP, LTD.

                             By:        2800 Industrial Inc., General Partner

                                        By:    /s/      Richard E. Anderson
                                              ------------------------------
                                              Richard E. Anderson
                                              Vice President

                                        2

<PAGE>   29

                                    EXHIBIT C

                                [Expansion Space]

         Except as provided below, on or before August 1, 1999, Tenant shall
lease for the remaining Term 37,334 additional square feet of rentable area in
the Building, constituting the remainder of the Building (the "Expansion
Space"). Notwithstanding the foregoing, if Tenant accepts delivery of, and
commences paying rent on, any portion of the expansion space under the Building
2 Lease prior to August 1, 1999, then the number of square feet of Expansion
Space which Tenant must lease prior to August 1, 1999, as provided above, shall
be reduced on a square foot for square foot basis; provided that any portion of
the Expansion Space not leased prior to August 1, 1999 must be leased by Tenant
on or before January 1, 2000. Tenant may commence its lease of the Expansion
Space in segments at various times provided that (i) it has leased all of the
Expansion Space on or before August 1, 1999, except for the number of square
feet of Expansion Space corresponding to the number of square feet of expansion
space leased by Tenant in Building 2 prior to August 1, 1999, which deferred
number of square feet of Expansion Space must be leased prior to January 1, 2000
(as provided above) (ii) each segment so leased (except for the last segment)
must be at least 5,000 square feet, and (iii) Tenant gives Landlord at least
forty-five (45) days prior written notice of the date on which it desires to
commence the lease of any given segment (each such date being referred to herein
as an ("Expansion Date").

         Landlord shall cause the Expansion Space (or applicable portion
thereof) to be in shell condition and made ready for Tenant's occupancy thirty
(30) days prior to the applicable Expansion Date, in accordance with the
procedures referenced in Exhibit B. The Allowance applicable to the Expansion
Space shall be a sum equal to $18.89 per rentable square foot in the Expansion
Space (or applicable portion thereof). Except as set forth in this Exhibit C,
all Expansion Space taken by Tenant shall be taken "as is" and Landlord shall
have no obligation to construct any leasehold improvements therein or to make
any alterations thereto.

         Tenant shall be required to commence paying rent on any applicable
portion of the Expansion Space upon the date that is the sooner to occur of (a)
the date that Tenant commences to occupy such space or (b) thirty (30) days
after Landlord delivers such portion of the Expansion Space in shell condition;
provided that Landlord shall not deliver the any portion of the Expansion Space
in shell condition prior to July 1, 1999, unless Tenant requests an earlier
delivery. If the applicable portion of the Expansion Space is not in shell
condition thirty (30) days prior to the applicable Expansion Date, Landlord
shall not be liable for damages therefor and Tenant shall accept possession of
such portion of the Expansion Space when Landlord tenders possession thereof to
Tenant in shell condition and Tenant's obligation to pay Base Rent and Operating
Expenses under Section 2.(b) of this Lease with respect to such portion of the
Expansion Space shall commence thirty (30) days after Landlord tenders
possession of such portion of the Expansion Space to Tenant in shell condition.
Tenant hereby acknowledges that if (x) Tenant is not required to commence paying
rent on any given portion of the Expansion Space on an earlier date, as provided
above, and (y) the outside rent commencement date for such Expansion Space is
not deferred until January 1, 2000, as provided above, then in any event, so
long as Landlord delivers such portion of the Expansion Space in shell condition
on or before July 1, 1999, Tenant's obligation to pay Base Rent and Operating
Expenses under

                                        3

<PAGE>   30

Section 2.(b) of this Lease with respect to any portion of the Expansion Space
so delivered shall commence on August 1, 1999.

         Except as provided in this Exhibit C, the leasing of the Expansion
Space shall be upon the same terms and conditions as the leasing of the initial
Premises and shall be upon and subject to all of the provisions of this Lease.
Upon any given Expansion Date: (i) the Base Rent payable by Tenant shall be
increased by the number of square feet contained within the applicable portion
of the Expansion Space multiplied by the dollar amount per square foot provided
in Section 2(a) of this Lease, (ii) the "Premises" (as defined in the Lease)
shall be deemed to include such portion the Expansion Space, and (iii) Tenant's
Proportionate Share shall be increased commensurately to reflect the addition of
such portion of the Expansion Space to the Premises. It being acknowledged that
at such time as Tenant has leased all of the Expansion Space, Tenant will be
leasing the entire Building and therefore its Proportionate Share of Operating
Expenses shall be 100%

         Notwithstanding anything to the contrary contained herein, Landlord
shall have the right to lease any portion of the Expansion Space to another
tenant or allow another party to use or occupy the Expansion Space, so long as
such lease or occupancy right is terminable on thirty (30) days notice and
expires thirty (30) days prior to the Expansion Date.

                                        4

<PAGE>   31

                       THIRD AMENDMENT TO LEASE AGREEMENT

         THIS THIRD AMENDMENT TO LEASE AGREEMENT is made and entered as of the
___ day of June 1999, by and between IXC COMMUNICATIONS SERVICES, INC.
("Tenant"), and KRAMER 34 HP, LTD. ("Landlord").

                                    RECITALS

         A. Pursuant to a Lease Agreement dated October 1, 1998 (as amended by
First Amendment to Lease Agreement dated December 29, 1998 and Second Amendment
to Lease Agreement dated May 13, 1999, the "Lease"), Landlord leased to Tenant
certain space in the building commonly known as "Kramer 3" in Austin, Texas, as
more fully described in the Lease.

         B. Landlord has leased to Tenant certain space in an adjacent building
commonly known as "Kramer 2", pursuant to a Lease Agreement dated of even date
herewith (the "Building 2 Lease").

         C. Landlord and Tenant desire to delay the commencement date of the
Building 2 Lease until August 23, 1999, which correspondingly changes the
expiration of the Term of the Lease and the date by which Tenant must lease the
Expansion Space pursuant to Exhibit "C" attached to the Lease.

                                    AMENDMENT

         In consideration of the premises, the mutual covenants and agreements
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant hereby amend
the Lease as follows:

         1. Paragraph 1 of the Second Amendment to Lease Agreement is hereby
replaced in its entirety by the following:

         Notwithstanding anything to the contrary contained in the Lease, it is
         hereby agreed that the initial Term shall be extended to be coterminous
         with the initial term of the Building 2 Lease. Section 1(b) of the
         Building 2 Lease (describing the term of the Building 2 Lease is
         reprinted below for reference:

                  The Lease term shall be seventy two (72) months, beginning on
                  the later of (i) sixty (60) days after substantial completion
                  of the Shell Improvements (as defined on Exhibit B) or (ii)
                  August 23, 1999 (the "COMMENCEMENT DATE"), and ending August
                  22, 2005 (the "TERM", which defined term shall include all
                  renewals and extensions of the Term, if any). Notwithstanding
                  the foregoing if the Commencement Date does not occur on
                  August 23, 1999, then the Term shall end seventy-two (72)
                  months after the Commencement Date.

                                        1

<PAGE>   32

         2. Each time the date "August 1, 1999" appears on Exhibit C to the
Lease (as the same was amended by the Second Amendment to Lease Agreement) it is
hereby replaced by the date August 23, 1999. Each time the date "July 1, 1999"
appears on Exhibit C to the Lease (as the same was amended by the Second
Amendment to Lease Agreement) it is hereby replaced by the date July 23, 1999.

         3. Except as defined differently herein or the context clearly requires
otherwise, all capitalized terms used in this Amendment shall have the meanings
ascribed to them under the Lease. Except as expressly amended hereby, the Lease
shall remain unchanged and in full force and effect, and is hereby ratified by
Landlord and Tenant.

         EXECUTED as of the date first written above.

                            TENANT:

                            IXC COMMUNICATIONS SERVICES, INC.

                            By:        /s/ Stuart K. Coppens
                                       -------------------------------------
                            Name:      Stuart K. Coppens
                            Title:     VP
                                              Approved as to form
                                               Legal dept.  ALJ

                            LANDLORD:

                            KRAMER 34 HP, LTD.

                            By:        2800 Industrial Inc., General Partner

                                       By:    /s/ R.E. Anderson
                                             ---------------------------------
                                              Richard E. Anderson
                                              Vice President

                                        2

<PAGE>   33

                            FOURTH AMENDMENT TO LEASE

         THIS FOURTH AMENDMENT TO LEASE (this "Amendment") is entered into as of
the 16th day of August, 1999 by and between THE PRUDENTIAL INSURANCE COMPANY OF
AMERICA, a New Jersey corporation ("Landlord") and IXC COMMUNICATIONS SERVICES,
INC., a Delaware corporation ("Tenant").

                                    RECITALS

         WHEREAS, Kramer 34 HP, Ltd., a Texas limited partnership, and Tenant
executed that certain Lease Agreement (the "Lease Agreement") dated October 1,
1998 covering 24,833 square feet of space located in Suite 100 of the building
knows as Kramer 3, located at 1825-A Kramer Lane, Austin, Texas 78758 (the
"Building"), as more particularly described therein;

         WHEREAS, the Lease Agreement has been amended pursuant to that certain
First Amendment to Lease Agreement, dated the 29th day of December 1998, that
certain Second Amendment to Lease Agreement dated the 13th day of May 1999 and
that certain Third Amendment to Lease Agreement dated the 3rd day of June 1999
(the Lease Agreement, as amended, the "Lease");

         WHEREAS, Landlord is the current owner of the Building and the
landlord under the lease;

         WHEREAS, Tenant desires to construct and install on the land upon which
the Building is located (the "Property") an antenna tower in the location shown
on Exhibit A attached hereto (the "Tower Space");

         WHEREAS, subject to the terms and conditions set forth herein, Landlord
has agreed to permit Tenant to construct and install the antenna tower on the
Property in the Tower Space; and

         WHEREAS, Landlord and Tenant desire to amend the Lease to reflect their
agreements as to the terms and conditions governing Tenant's construction,
installation, and operation of the antenna tower in the Tower Space.

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants between the parties herein contained, and for good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged,
Landlord and Tenant hereby agree as follows:

                                   AGREEMENT:

         1. ANTENNA TOWER. Landlord hereby grants Tenant a license (the "Tower
License"), subject to the approval of the City of Austin and all other
governmental authorities having jurisdiction over the Property and Tenant's
operations, to construct, install, operate and maintain an antenna tower and
related cabling, improvements and equipment on the Property in the Tower Space

                                       1

<PAGE>   34

(such tower and related cabling and equipment, collectively, the "Antenna
Tower") in accordance with plans and specifications approved by Landlord, which
approval shall not be unreasonably withheld. Tenant shall, at Tenant's sole cost
and expense, construct a fence around the Tower Space pursuant to plans and
specifications approved by Landlord, which approval shall not be unreasonably
withheld. All work in connection with the construction and installation of the
Antenna Tower shall be performed in a good and workmanlike manner in accordance
with all applicable laws and by contractors approved by Landlord, which approval
shall not be unreasonably withheld. Tenant's contractors shall comply at all
times with Landlord's constructions rules applicable to the Property, including
contractor insurance requirements of Landlord. Upon completion of the Antenna
Tower, Tenant shall deliver to Landlord sworn statements setting forth the names
of all contractors and subcontractors who performed work on the Antenna Tower
and final lien waivers from all such contractors and subcontractors. Throughout
the construction and installation of the Antenna Tower, Tenant, at its expense,
shall carry, or cause to be carried, construction risk insurance under which
Landlord shall be named as an additional insured.

         2. PLANS AND SPECIFICATIONS. Prior to installation of the Tower
Antenna, Tenant shall deliver to Landlord for its approval plans and
specifications therefor which are sufficiently detailed to allow construction
and installation of the Tower Antenna depicted thereon to be performed in a good
and workmanlike manner. If the construction and installation will affect the
Building's structure or mechanical or electrical systems, then the plans and
specifications therefor must be prepared by licensed engineer reasonably
acceptable to Landlord. Landlord's approval of any plans and specifications
shall not be a representation that the plans or the work depicted thereon will
comply with law or be adequate for any purpose, but shall merely be Landlord's
consent to performance of the work. Tenant shall furnish Landlord a complete set
of as builts at the completion of all work.

         3. COMPLIANCE WITH LAWS. Prior to the installation of the Antenna
Tower, Tenant shall secure and shall at all times thereafter maintain all
required approvals and permits of the Federal Communications Commission and all
other government authorities having jurisdiction over the Antenna Tower, the
Property and/or Tenant's business, including it communications, operations and
facilities. Tenant shall at all times comply with all laws and ordinances and
all rules and regulations of municipal, state and federal governmental
authorities relating to the installation, maintenance, height, location, use,
operations, and removal of the Antenna Tower and shall fully indemnify Landlord
against any loss, cost, or expense which may be sustained or incurred by it as a
result of the installation, maintenance, operation, or removal of the Antenna
Tower, EXCEPT IF THE SAME IS CAUSED BY OR RESULTS FROM THE GROSS NEGLIGENCE OR
WILLFUL MISCONDUCT, BUT NOT THE NEGLIGENCE OF LANDLORD. Landlord makes no
representation that applicable laws, ordinances or regulations permit the
installation or operation of the Antenna Tower at the Property.

         4. MAINTENANCE OF THE ANTENNA TOWER. Tenant, at its expense, shall be
solely responsible for and shall maintain the Antenna Tower in a safe,
structural, sound, clean and sightly condition and shall indemnify and save
harmless Landlord against all liens and claims of mechanics

                                        2

<PAGE>   35

and materialmen furnishing labor and materials in the construction and
maintenance of same. Tenant shall establish and observe safety procedures
relative to the operation, maintenance, and repair of the Antenna Tower. Tenant
shall not make any alterations, additions or improvements in or to the Tower
Space or the Antenna Tower without the prior written consent of Landlord, which
consent shall not be unreasonably withheld.

         5. REMOVAL OF ANTENNA TOWER. At the termination of the Lease, the
Antenna Tower shall at Landlord's request be removed by Tenant, at Tenant's sole
cost and expense, and Tenant shall restore the Property, the Building and the
Tower Space to as similar of a condition as is reasonably practicable to that
which existed immediately prior to installation of the Antenna Tower.

         6. LIMITATION OF LIABILITY. Notwithstanding any provision in the Lease
to the contrary, Landlord shall not have any liability arising out of or in
connection with the Tower Space, the Antenna Tower or Tenant's installation of
the Antenna Tower or Tenant's use of the Tower Space or any other areas on the
Property or in the Building where Tenant's equipment related to the use of the
Antenna Tower is located.

         7. INSURANCE. All insurance required under the Lease to be maintained
by Tenant with respect to the Premises shall also be maintained by Tenant with
respect to the Tower Space.

         8. AUTHORITY. Tenant and each person signing this Amendment on behalf
of Tenant represents to Landlord as follows; (a) Tenant is a duly incorporated
and validly existing under the laws of the State of Texas, (b) Tenant has and is
qualified to do business in Texas, (iii) Tenant has the full right and authority
to enter into this Amendment, and (iv) each person signing on behalf of Tenant
was and continues to be authorized to do so.

         9. DEFINED TERMS. All terms not otherwise defined herein shall have the
same meaning as assigned to them in the Lease. Except as amended hereby, the
Lease shall remain in full force and effect in accordance with its terms and is
hereby ratified. In the event of a conflict between the Lease and this
Amendment, this Amendment shall control.

         10. EXHIBITS. Each Exhibit attached hereto is made a part hereof for
all purposes.

         11. NO REPRESENTATIONS. Landlord and Landlord's agents have made no
representations or promises, express or implied, in connection with the Tower
Space or this Amendment, except as expressly set forth herein.

         12. ENTIRE AGREEMENT. This Amendment, together with the Lease, contains
all of the agreements of the parties hereto with respect to any matter covered
or mentioned in this Amendment or the Lease, and no prior agreement,
understanding or representation pertaining to any such matter shall be effective
for any purpose.

                                        3

<PAGE>   36

         IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date first above written.

                        LANDLORD:

                        THE PRUDENTIAL INSURANCE COMPANY OF
                        AMERICA, a New Jersey corporation

                        By:        HILL PARTNERS MANAGEMENT
                        COMPANY, INC., ITS AUTHORIZED AGENT

                        By:       /s/ Beth Ann Signor
                                  -------------------------------------
                        Name:     Beth Ann Signor
                        Title:    President

                        TENANT:

                        IXC COMMUNICATIONS SERVICES, INC., a
                        Delaware Corporation

                         By:       /s/ Kihm Schroeder
                                   -------------------------------------
                         Name:     Kihm Schroeder
                         Title:    VP Network Planning

                                        4

<PAGE>   37

                                    EXHIBIT A

                                   TOWER SPACE

                                        5

<PAGE>   38

                       FIFTH AMENDMENT TO LEASE AGREEMENT

         THIS FIFTH AMENDMENT TO LEASE AGREEMENT is made and entered as of the
1st day of October 1999, by and between IXC COMMUNICATIONS SERVICES, INC.
("Tenant"), and THE PRUDENTIAL INSURANCE COMPANY OF AMERICA ("Landlord").

                                    RECITALS

         A. Pursuant to a Lease Agreement dated October 1, 1998 (as amended by
First, Second, Third and Fourth Amendments to Lease Agreement, the "Lease"),
Kramer 34 HP, Ltd. (predecessor-in-interest to Landlord) leased to Tenant
certain space in the building commonly known as "Kramer 3" in Austin, Texas, as
more fully described in the Lease.

         B. Pursuant to Exhibit "C" to the Lease, Tenant has delivered notice to
Landlord that it intends to commence its lease of 17,183 square feet out of the
Expansion Space, as such space is shown on EXHIBIT "A" attached hereto (the
"Current Expansion Space").

         C. Although the terms of Exhibit "C" to the Lease do not require an
amendment to the Lease in order to evidence a take-down of Expansion Space
(i.e., the expansion provisions in the Lease are self-operative), Landlord and
Tenant desire to enter into this Amendment in order to set the date on which
Tenant will be required to commence paying rent on the Current Expansion Space.

                                    AMENDMENT

         In consideration of the premises, the mutual covenants and agreements
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant hereby amend
the Lease as follows:

         1. Notwithstanding anything to the contrary contained in Exhibit "C" to
the Lease, it is hereby agreed that Tenant shall commence paying rent on the
Current Expansion Space on the earlier of (i) the date Tenant commences to
occupy such space, or (ii) October 15, 1999. Furthermore, Landlord hereby
delivers the Current Expansion Space to Tenant in shell condition, and Tenant
hereby acknowledges and accepts such delivery. Effective as of the date Tenant
is required to commence paying rent on the Current Expansion Space, Tenant's
Proportionate Share of Operating Expenses shall be increased to 67.6%. Except as
provided above, Tenant's lease of the Current Expansion Space shall be in
accordance with the terms and provisions of Exhibit "C" to the Lease. Nothing
contained herein shall relieve Landlord of its obligation to deliver, or Tenant
to lease, the balance of the Expansion Space as and when required pursuant to
Exhibit "C" to the Lease.

         2. Except as defined differently herein or the context clearly requires
otherwise, all capitalized terms used in this Amendment shall have the meanings
ascribed to them under the

                                        1

<PAGE>   39

Lease. Except as expressly amended hereby, the Lease shall remain unchanged and
in full force and effect, and is hereby ratified by Landlord and Tenant.

EXECUTED as of the date first written above.

                              TENANT:

                              IXC COMMUNICATIONS SERVICES, INC.

                              By:       /s/ Mike R. Jones
                                       -------------------------------------
                              Name:     Mike R. Jones, Vice President
                              Title:    Facilities, Construction & Engineering

                              LANDLORD:

                              THE PRUDENTIAL INSURANCE COMPANY
                              OF AMERICA

                              By:       Hill Partners Management Company,
                                        Inc., its authorized agent

                                        By:     /s/   Richard E. Anderson
                                               ------------------------------
                                                Richard E. Anderson
                                                Vice President

                                        2

<PAGE>   40

                                    EXHIBIT A

                                    (DIAGRAM)

                                        3

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