<PAGE>   1
                                                                   EXHIBIT 10.23


THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 AS
AMENDED, OR ANY STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR SALE,
PLEDGED, OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT
RELATED THERETO OR AN OPINION OF COUNSEL (WHICH MAY BE COMPANY COUNSEL)
REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED
UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE
SECURITIES LAWS.

                               WARRANT AGREEMENT

             TO PURCHASE SHARES OF THE SERIES C PREFERRED STOCK OF

                                    COLO.COM

              DATED AS OF OCTOBER 22, 1999 (THE "EFFECTIVE DATE")

     WHEREAS, COLO.COM, a California corporation (the "Company") has entered
into a Loan and Security Agreement dated as of October 22, 1999, and related
Promissory Note(s) (collectively, the "Loans") with Comdisco, Inc., a Delaware
corporation (the "Warrantholder"); and

     WHEREAS, the Company desires to grant to Warrantholder, in consideration
for such Loans, the right to purchase shares of its Series C Preferred Stock;

     NOW, THEREFORE, in consideration of the Warrantholder executing and
delivering such Loans and in consideration of mutual covenants and agreements
contained herein, the Company and Warrantholder agree as follows:

1.   GRANT OF THE RIGHT TO PURCHASE PREFERRED STOCK.

     For value received, the Company hereby grants to the Warrantholder, and
the Warrantholder is entitled, upon the terms and subject to the conditions
hereinafter set forth, to subscribe for and purchase from the Company that
number of fully paid and assessable shares of the Company's Series C Preferred
Stock ("Preferred Stock") equal to $560,000 divided by the Exercise Price
("Exercise Price"). The Exercise Price shall equal to the sum of $0.50 per
share (the "Last Round") plus the product of (a) the difference between the
price per share of the next round of equity financing (the "Next Round") and
the Last Round, multiplied by (b) the fraction resulting from dividing (x) the
number of days from the date of closing of the Last Round (ie. April 27, 1999)
to the date of execution of the Leases, by (y) the number of days from the date
of the closing of the Last Round to the date of closing of the Next Round;
provided however, if the Next Round is not successfully completed by December
31, 1999, then the Exercise Price shall be equal to $0.50 per share.

     The Next Round shall be defined as the earlier of Company's (i) initial
public offering, (ii) merger or (iii) private equity round. The number and
purchase price of such shares are subject to adjustment as provided in Section
8 hereof.

2.   TERM OF THE WARRANT AGREEMENT.

     Except as otherwise provided for herein, the term of this Warrant
Agreement and the right to purchase Preferred Stock as granted herein shall
commence on the Effective Date and shall be exercisable for a period of (i) ten
(10) years or (ii) five (5) years from the effective date of the Company's
initial public offering, whichever is longer.

     If at any time the Company proposes to merge with or into any other
corporation, effect a reorganization, or sell or convey all or substantially
all of its assets to any other entity in a transaction in which the
shareholders of the Company immediately before the transaction own immediately
after the transaction less than a majority of the outstanding voting securities
of the surviving entity (or its parent), then the Company shall give the
Warrantholder thirty (30) days notice of the proposed effective date of the
transaction and, if the  Warrant has not been exercised by the effective date
of the transaction, the Warrant shall terminate.



                                      -1-
<PAGE>   2

3.   EXERCISE OF THE PURCHASE RIGHTS.

     The purchase rights set forth in the Warrant Agreement are exercisable by
the Warrantholder, in whole or in part, at any time, or from time to time,
prior to the expiration of the term set forth in Section 2 above, by tendering
to the Company at its principal office a notice of exercise in the form
attached hereto as Exhibit I (the "Notice of Exercise"), duly completed and
executed. Promptly upon receipt of the Notice of Exercise and the payment of
the purchase price in accordance with the terms set forth below, and in no
event later than twenty-one (21) days thereafter, the Company shall issue to
the Warrantholder a certificate for the number of shares of Preferred Stock
purchased and shall execute the acknowledgment of exercise in the form attached
hereto as Exhibit II (the "Acknowledgment of Exercise") indicating the number
of shares which remain subject to future purchases, if any.

     The Exercise Price may be paid at the Warrantholder's election either (i)
by cash or check, or (ii) by surrender of Warrants ("Net Issuance") as
determined below. If the Warrantholder elects the Net Issuance method, the
Company will issue Preferred Stock in accordance with the following formula:

               X = Y(A-B)
                   ------
                     A

     Where:    X =  the number of shares of Preferred Stock to be issued to the
                      Warrantholder.

               Y =  the number of shares of Preferred Stock requested to be
                      exercised under this Warrant Agreement.

               A =  the fair market value of one (1) share of Preferred Stock.

               B =  the Exercise Price.

     For purposes of the above calculation, current fair market value of
Preferred Stock shall mean with respect to each share of Preferred Stock:

          (i)  if the exercise is in connection with an initial public offering
     of the Company's Common Stock, and if the Company's Registration Statement
     relating to such public offering has been declared effective by the SEC,
     then the fair market value per share shall be the product of (x) the
     initial "Price to Public" specified in the final prospectus with respect to
     the offering and (y) the number of shares of Common Stock into which each
     share of Preferred Stock is convertible at the time of such exercise;

          (ii) If this Warrant is exercised after, and not in connection with
     the Company's initial public offering, and:

               (a) if traded on a securities exchange, the fair market value
          shall be deemed to be the product of (x) the average of the closing
          prices over a five (5) day period ending three days before the day
          the current fair market value of the securities is being determined
          and (y) the number of shares of Common Stock into which each share of
          Preferred Stock is convertible at the time of such exercise; or

               (b) if actively traded over-the-counter, the fair market value
          shall be deemed to be the product of (x) the average of the closing
          bid and asked prices quoted on the NASDAQ system (or similar system)
          over the five (5) day period ending three days before the day the
          current fair market value of the securities is being determined and
          (y) the number of shares of Common Stock into which each share of
          Preferred Stock is convertible at the time of such exercise;

          (iii) If at any time the Common Stock is not listed on any securities
     exchange or quoted in the NASDAQ System or the over-the-counter market, the
     current fair market value of Preferred Stock shall be the product of (x)
     the highest price per share which the Company could obtain from a willing
     buyer (not a current employee or director) for shares of Common Stock sold
     by the Company, from authorized but unissued shares, as determined in good
     faith by its Board of Directors and (y) the number of shares of Common
     Stock into which each share of Preferred Stock is convertible at the time
     of such exercise, unless the Company shall become subject to a merger,
     acquisition or other consolidation pursuant to which the Company is not the
     surviving party, in which case the fair market value of Preferred Stock
     shall be deemed



                                      -2-
<PAGE>   3
     to be the value received by the holders of the Company's Preferred Stock on
     a common equivalent basis pursuant to such merger or acquisition.

     Upon partial exercise by either cash or Net Issuance, the Company shall
promptly issue an amended Warrant Agreement representing the remaining number
of shares purchasable hereunder. All other terms and conditions of such
amended Warrant Agreement shall be identical to those contained herein,
including, but not limited to the Effective Date hereof.

4.   RESERVATION OF SHARES.

     As of March 31, 2000 and during the term of this Warrant Agreement
thereafter, the Company will at all times have authorized and reserved a
sufficient number of shares of its Preferred Stock to provide for the exercise
of the rights to purchase Preferred Stock as provided for herein.

5.   NO FRACTIONAL SHARES OR SCRIP.

     No fractional shares or scrip representing fractional shares shall be
issued upon the exercise of the Warrant, but in lieu of such fractional shares
the Company shall make a cash payment therefor upon the basis of the Exercise
Price then in effect.

8.   NO RIGHTS AS SHAREHOLDER.

     This Warrant Agreement does not entitle the Warrantholder to any voting
rights or other rights as a shareholder of the Company prior to the exercise of
the Warrant.

7.   WARRANTHOLDER REGISTRY.

     The Company shall maintain a registry showing the name and address of the
registered holder of this Warrant Agreement.

8.   ADJUSTMENT RIGHTS.

     The purchase price per share and the number of shares of Preferred Stock
purchasable hereunder are subject to adjustment, as follows:

     (a)  Merger and Sale of Assets. If at any time there shall be a capital
reorganization of the shares of the Company's stock (other than a combination,
reclassification, exchange or subdivision of shares otherwise provided for
herein), or a merger or consideration of the Company with or into another
corporation whether or not the Company is the surviving corporation, or the
sale of all or substantially all of the Company's properties and assets to any
other person (hereinafter referred to as a "Merger Event"), then, as a part of
such Merger Event, lawful provision shall be made so that the Warrantholder
shall thereafter be entitled to receive, upon exercise of the Warrant, the
number of shares of preferred stock or other securities of the successor
corporation resulting from such Merger Event, equivalent in value to that which
would have been issuable if Warrantholder had exercised this Warrant
immediately prior to the Merger Event. In any such case, appropriate adjustment
(as determined in good faith by the Company's Board of Directors) shall be made
in the application of the provisions of this Warrant Agreement with respect to
the rights and interest of the Warrantholder after the Merger Event to the end
that the provisions of this Warrant Agreement (including adjustments of the
Exercise Price and number of shares of Preferred Stock purchasable) shall be
applicable to the greatest extent possible.

     (b)  Reclassification of Shares. If the Company at any time shall, by
combination, reclassification, exchange or subdivision of securities or
otherwise, change any of the securities as to which purchase rights under this
Warrant Agreement exist into the same or a different number of securities of
any other class or classes, this Warrant Agreement shall thereafter represent
the right to acquire such number and kind of securities as would have been
issuable as the result of such change with respect to the securities which were
subject to the purchase rights under this Warrant Agreement immediately prior
to such combination, reclassification, exchange, subdivision or other change.

     (c)  Subdivision or Combination of Shares. If the Company at any time
shall combine or subdivide its Preferred Stock, the Exercise Price shall be
proportionally decreased in the case of a subdivision, or proportionately
increased in the case of a combination.


                                      -3-
<PAGE>   4
     (d) Right to Purchase Additional Stock. If the Company has not paid any
Promissory Note(s) entered into pursuant to the Loan(s) in its entirety by the
Maturity Date (as defined in the applicable Subordinated Promissory Note(s)),
then for each additional month, or portion thereof, thereafter that the
outstanding principal is not paid, Warrantholder shall have the right to
purchase from the Company, at the Exercise Price (adjusted as set forth
herein), an additional number of shares of Preferred Stock which number shall
be determined by (i) multiplying the outstanding principal amount which due but
unpaid by 1% and (ii) dividing the product thereof by the Exercise Price.

     (f) Antidilution Rights. Additional antidilution rights applicable to the
Preferred Stock purchasable hereunder are as set forth in the Company's
Articles of incorporation, as amended through the Effective Date, a true and
complete copy of which is attached hereto as Exhibit __ (the "Charter"). The
Company shall promptly provide the Warrantholder with any restatement,
amendment, modification or waiver of the Charter. The Company shall provide
Warrantholder the same notices that it provides holders of its Preferred Stock.

     (g) Notice of Adjustments. If: (i) the Company shall declare any dividend
or distribution upon its stock, whether in cash, property, stock or other
securities; (ii) the Company shall offer for subscription prorata to the
holders of any class of its Preferred or other convertible stock any additional
shares of stock of any class or other rights; (iii) there shall be any Merger
Event; (iv) there shall be an initial public offering; or (v) there shall be any
voluntary dissolution, liquidation or winding up of the Company; then, in
connection with each such event, the Company shall send to the Warrantholder:
(A) at least twenty (20) days' prior written notice of the date on which the
books of the Company shall close or a record shall be taken for such dividend,
distribution, subscription rights (specifying the date on which the holders of
Preferred Stock shall be entitled thereto) or for determining rights to vote in
respect of such Merger Event, dissolution, liquidation or winding up; (B) in
the case of any such Merger Event, dissolution, liquidation or winding up, at
least twenty (20) days' prior written notice of the date when the same shall
take place (and specifying the date on which the holders of Preferred Stock
shall be entitled to exchange their Preferred Stock for securities or other
property deliverable upon such Merger Event, dissolution, liquidation or
winding up); and (C) in the case of a public offering, the Company shall give
the Warrantholder at least twenty (20) days written notice prior to the
effective date thereof.

     Each such written notice shall set forth, in reasonable detail, (i) the
event requiring the adjustment, (ii) the amount of the adjustment, (iii) the
method by which such adjustment was calculated, (iv) the Exercise Price, and
(v) the number of shares subject to purchase hereunder after giving effect to
such adjustment, and shall be given by first class mail, postage prepaid,
addressed to the Warrantholder, at the address as shown on the books of the
Company.

     (h) Timely Notice. Failure to timely provide such notice required by
subsection (g) above shall entitle Warrantholder to retain the benefit of the
applicable notice period notwithstanding anything to the contrary contained in
any insufficient notice received by Warrantholder. The notice period shall
begin on the date Warrantholder actually receives a written notice containing
all the information specified above.

9.   REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.

     (a) Reservation of Preferred Stock. The Company covenants that no later
than March 31, 2000, the Preferred Stock issuable upon exercise of the
Warrantholder's rights will be duly and validly reserved and, when issued in
accordance with the provisions of this Warrant Agreement, will be validly
issued, fully paid and non-assessable, and will be free of any taxes, liens,
charges or encumbrances of any nature whatsoever; provided, however, that the
Preferred Stock issuable pursuant to this Warrant Agreement may be subject to
restrictions on transfer under state and/or Federal securities laws. The
Company has made available to the Warrantholder true, correct and complete
copies of its Charter and Bylaws, as amended. The issuance of certificates for
shares of Preferred Stock upon exercise of the Warrant Agreement shall be made
without charge to the Warrantholder for any issuance tax in respect thereof, or
other cost incurred by the Company in connection with such exercise and the
related issuance of shares of Preferred Stock. The Company shall not be
required to pay any tax which may be payable in respect of any transfer
involved and the issuance and delivery of any certificate in a name other than
that of the Warrantholder.

     (b) Due Authority. The execution and delivery by the Company of this
Warrant Agreement and the performance of all obligations of the Company
hereunder, including the issuance to Warrantholder of the right to acquire the
shares of Preferred Stock, have been duly authorized by all necessary corporate
action on the part of the Company, and the Loans and this Warrant Agreement are
not inconsistent with the Company's Charter or Bylaws, do not contravene any
law or governmental rule, regulation or order applicable to it, do not and will
not contravene any provision of, or constitute a default under, any indenture,
mortgage, contract or other instrument to which it is a



                                      -4-
<PAGE>   5
party or by which it is bound, and the Loans and this Warrant Agreement
constitute legal, valid and binding agreements of the Company, enforceable in
accordance with their respective terms except that, at the Effective Date,
there is not a sufficient number of shares of Series C Preferred Stock reserved
for issuance in the Articles of Incorporation, to provide the Preferred stock
upon exercise of the Warrantholder's rights.

     (c)  Consents and Approvals. No consent or approval of, giving of notice
to, registration with, or taking of any other action in respect of any state,
Federal or other governmental authority or agency is required with respect to
the execution, delivery and performance by the Company of its obligations under
this Warrant Agreement, except for the filing of notices pursuant to Regulation
D under the 1933 Act and any filing required by applicable state securities
law, which filings will be effective by the time required thereby.

     (d)  Issued Securities. All issued and outstanding shares of Common Stock,
Preferred Stock or any other securities of the Company have been duly
authorized and validly issued and are fully paid and nonaccessable. All
outstanding shares of Common Stock, Preferred Stock, and any other securities
were issued in full compliance with all Federal and state securities laws. In
addition:

          (i)   The authorized capital of the Company consists of (A) 50,000,000
     shares of Common Stock, of which 9,362,864 shares are issued and
     outstanding, and (B) 29,750,000 shares of preferred stock, of which
     28,761,730 shares are issued and outstanding and are convertible into
     28,761,730 shares of Common Stock.

          (ii)  The Company has reserved (A) 5,471,357 shares of Common Stock
     for issuance under its 1998 Stock Plan, under which 3,521,500 options are
     outstanding at an exercise price ranging from $0.03 to $0.50 per share.
     Other than outstanding warrants for the purchase of 545,500 shares of
     Common Stock, there are no other options, warrants, conversion privileges
     or other rights presently outstanding to purchase or otherwise acquire any
     authorized but unissued shares of the Company's capital stock or other
     securities of the Company.

          (iii) In accordance with the Company's Articles of Incorporation, no
     shareholder of the Company has preemptive rights to purchase new issuances
     of the Company's capital stock.

     (e)  Insurance. The Company has in full force and effect insurance
policies, with extended coverage, insuring the Company and its property and
business against such losses and risks, and in such amounts, as are customary
for corporations engaged in a similar business and similarly situated and as
otherwise may be required pursuant to the terms of any other contract or
agreement.

     (f)  Other Commitments to Register Securities. Except as set forth in the
Amended and Restated Investors Rights Agreement by and among the Company and
certain Preferred Stock investors, the Company is not, pursuant to the terms of
any other agreement currently in existence, under any obligation to register
under the 1933 Act any of its presently outstanding securities or any of its
securities which may hereafter be issued.

     (g)  Exempt Transaction. Subject to the accuracy of the Warrantholder's
representations in Section 10 hereof, the issuance of the Preferred Stock upon
exercise of this Warrant will constitute a transaction exempt from (i) the
registration requirements of Section 5 of the 1933 Act, in reliance upon
Section 4(2) thereof, and (ii) the qualification requirements of the applicable
state securities laws.

     (h)  Compliance with Rule 144. At the written request of the
Warrantholder, who proposes to sell Preferred Stock issuable upon the exercise
of the Warrant in compliance with Rule 144 promulgated by the Securities and
Exchange Commission, the Company shall furnish to the Warrantholder, within
ten days after receipt of such request, a written statement confirming the
Company's compliance with the filing requirements of the Securities and
Exchange Commission as set forth in such Rule, as such Rule may be amended
from time to time.

10.  REPRESENTATIONS AND COVENANTS OF THE WARRANTHOLDER.

     This Warrant Agreement has been entered into by the Company in reliance
upon the following representations and covenants of the Warrantholder:

     (a)  Investment Purpose. The right to acquire Preferred Stock or the
Preferred Stock issuable upon exercise of the Warrantholder's rights contained
herein will be acquired for investment and not with a view to the sale

                                      -6-



<PAGE>   6
or distribution of any part thereof, and the Warrantholder has no present
intention of selling or engaging in any public distribution of the same except
pursuant to a registration or exemption.

     (b)  Private Issue. The Warrantholder understands (i) that the Preferred
Stock issuable upon exercise of this Warrant is not registered under the 1933
Act or qualified under applicable state securities laws on the ground that the
issuance contemplated by this Warrant Agreement will be exempt from the
registration and qualifications requirements thereof, and (ii) that the
Company's reliance on such exemption is predicated on the representations set
forth in this Section 10.

     (c)  Disposition of Warrantholder's Rights. In no event will the
Warrantholder make a disposition of any of its rights to acquire Preferred
Stock or Preferred Stock issuable upon exercise of such rights unless and until
(i) it shall have notified the Company of the proposed disposition, and (ii) if
requested by the Company, it shall have furnished the Company with an opinion
of counsel (which counsel may either be inside or outside counsel to the
Warrantholder) satisfactory to the Company and its counsel to the effect that
(A) appropriate action necessary for compliance with the 1933 Act has been
taken, or (B) an exemption from the registration requirements of the 1933 Act
is available. Notwithstanding the foregoing, the restrictions imposed upon the
transferability of any of its rights to acquire Preferred Stock or Preferred
Stock issuable on the exercise of such rights do not apply to transfers from
the beneficial owner of any of the forementioned securities to its nominee or
from such nominee to its beneficial owner, and shall terminate as to any
particular share of Preferred Stock when (1) such security shall have been
effectively registered under the 1933 Act and sold by the holder thereof in
accordance with such registration or (2) such security shall have been sold
without registration in compliance with Rule 144 under the 1933 Act, or (3) a
letter shall have been issued to the Warrantholder at its request by the staff
of the Securities and Exchange Commission or a ruling shall have been issued to
the Warrantholder at its request by such Commission stating that no action
shall be recommended by such staff or taken by such Commission, as the case may
be, if such security is transferred without registration under the 1933 Act in
accordance with the conditions set forth in such letter or ruling and such
letter or ruling specifies that no subsequent restrictions on transfer are
required. Whenever the restrictions imposed hereunder shall terminate, as
hereinabove provided, the Warrantholder or holder of a share of Preferred Stock
then outstanding as to which such restrictions have terminated shall be
entitled to receive from the Company, without expense to such holder, one or
more new certificates for the Warrant or for such shares of Preferred Stock not
bearing any restrictive legend.

     (d)  Financial Risk. The Warrantholder has such knowledge and experience
in financial and business matters as to be capable of evaluating the merits and
risks of its Investment, and has the ability to bear the economic risks of its
investment.

     (e)  Risk of No Registration. The Warrantholder understands that if the
Company does not register with the Securities and Exchange Commission pursuant
to Section 12 of the 1934 Act (the "1934 Act"), or file reports pursuant to
Section 15(d), of the 1934 Act, or if a registration statement covering the
securities under the 1933 Act is not in effect when it desires to sell (i) the
rights to purchase Preferred Stock pursuant to this Warrant Agreement, or (ii)
the Preferred Stock issuable upon exercise of the right to purchase, it may be
required to hold such securities for an indefinite period. The Warrantholder
also understands that any sale of its rights of the Warrantholder to purchase
Preferred Stock or Preferred Stock which might be made by it in reliance upon
Rule 144 under the 1933 Act may be made only in accordance with the terms and
conditions of that Rule.

     (f)  Accredited Investor. Warrantholder is an "accredited investor" within
the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

11.  TRANSFERS.

     Subject to the terms and conditions contained in Section 10 hereof and
further subject to the written consent of the Company on 30 days written
notice, this Warrant Agreement and all rights hereunder are transferable in
whole or in part by the Warrantholder and any successor transferee, provided,
however, in no event shall the number of transfers of the rights and interests
in all of the Warrants exceed three (3) transfers. The transfer shall be
recorded on the books of the Company upon receipt by the Company of a notice of
transfer in the form attached hereto as Exhibit III (the "Transfer Notice"),
at its principal offices and the payment to the Company of all transfer taxes
and other governmental charges imposed on such transfer.


                                      -6-
<PAGE>   7
12.   MARKET STANDOFF

      In connection with the initial public offering of the Company's
securities, the Warrantholder agrees not to sell, make any short sale of, loan,
grant any option for the purchase of, or otherwise dispose of or hedge if
ownership risks of any securities of the Company (other than those included in
the registration) without the prior written consent of the Company for a period
of one hundred eighty (180) days from the effective date of such registration.
The Warrantholder agrees that the Company may instruct its transfer agent to
place stock-transfer notifications in its records to enforce the provisions of
this Section 12. The Warrantholder agrees to execute a reasonable and customary
agreement reflecting the foregoing as may be requested by the managing
underwriters at the time of the Company's initial underwritten public offering.

13.   MISCELLANEOUS.

      (a)   Effective Date. The provisions of this Warrant Agreement shall be
construed and shall be given effect in all respects as if it had been executed
and delivered by the Company on the date hereof. This Warrant Agreement shall
be binding upon any successors or assigns of the Company.

      (b)   Attorney's Fees. In any litigation, arbitration or court
proceeding between the Company and the Warrantholder relating hereto, the
prevailing party shall be entitled to reasonable attorneys' fees and expenses
and all costs of proceedings incurred in enforcing this Warrant Agreement.

      (c)   Governing Law. This Warrant Agreement shall be governed by and
construed for all purposes under and in accordance with the laws of the State
of Illinois.

      (d)   Counterparts. This Warrant Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

      (e)   Notices. Any notice required or permitted hereunder shall be given
in writing and shall be deemed effectively given upon personal delivery,
facsimile transmission (provided that the original is sent by personal delivery
or mail as hereinafter set forth) or seven (7) days after deposit in the United
States mail, by registered or certified mail, addressed: (1) to the
Warrantholder at 6111 North River Road, Rosemont, Illinois 60018, attention:
Venture Lease Administration, cc: Legal Department, attn.: General Counsel,
(and/or, if by facsimile, (847) 518-5465 and (847) 518-5088 and (ii) to the
Company at 2000 sierra Point, 6th Floor, Brisbane, CA 84005, Attention: Chief
Financial Officer (and/or if by facsimile, (650) 244-7727) or at such other
address as any such party may subsequently designate by written notice to the
other party.

      (f)   Remedies. In the event of any default hereunder, the non-defaulting
party may proceed to protect and enforce its rights either by suit in equity
and/or by action at law, including but not limited to an action for damages as
a result of any such default, and/or an action for specific performance for any
default where Warrantholder will not have an adequate remedy at law and where
damages will not be readily ascertainable. The Company expressly agrees that it
shall not oppose an application by the Warrantholder or any other person
entitled to the benefit of this Agreement requiring specific performance of any
or all provisions hereof or enjoining the Company from continuing to commit any
such breach of this Agreement.

      (g)   No Impairment of Rights. The Company will not, by amendment of its
Charter or through any other means, avoid or seek to avoid the observance or
performance of any of the terms of this Warrant, but will at all times in good
faith assist in the carrying out of all such terms and in the taking of all such
actions as may be necessary or appropriate in order to protect the rights of the
Warrantholder against impairment.

      (h)   Survival. The representations, warranties, covenants and conditions
of the respective parties contained herein or made pursuant to this Warrant
Agreement shall survive the execution and delivery of this Warrant Agreement.

      (i)   Severability. In the event any one or more of the provisions of
this Warrant Agreement shall for any reason be held invalid, illegal or
unenforceable, the remaining provisions of this Warrant Agreement shall be
unimpaired, and the invalid, illegal or unenforceable provision shall be
replaced by a mutually acceptable valid, legal and enforceable provision, which
comes closest to the intention of the parties underlying the invalid, illegal
or unenforceable provision.



                                      -7-
<PAGE>   8
     (j)  Amendments.  Any provision of this Warrant Agreement may be amended
by a written instrument signed by the Company and by the Warrantholder.

     (k)  Additional Documents.  The Company, upon execution of this Warrant
Agreement, shall provide the Warrantholder with certified resolutions with
respect to the representations, warranties and covenants set forth in
subparagraphs (a) through (d), (f) and (g) of Section 9 above. The Company
shall also supply such other documents as the Warrantholder may from time to
time reasonably request.

     IN WITNESS WHEREOF, the parties hereto have caused this Warrant Agreement
to be executed by its offices thereunto duly authorized as of the Effective
Date.

                                        COMPANY: COLO.COM


                                        By: /s/ GARY J. SANDERS
                                            -----------------------------

                                        Title: CFO
                                               --------------------------


                                        WARRANTHOLDER: COMDISCO, INC.


                                        By: /s/ JAMES LABE
                                            -----------------------------

                                        Title: James Labe, President
                                               Comdisco Ventures Division
                                               --------------------------

                                                       OCT 29 1998



                                      -8-
<PAGE>   9
                                   EXHIBIT 1

                               NOTICE OF EXERCISE

TO:  _______________________

(1)  The undersigned Warrantholder hereby selects to purchase _________ shares
     of the Series ___ Preferred Stock of ___________________, pursuant to the
     terms of the Warrant Agreement dated the ____ day of _____________, 19___
     (the "Warrant Agreement") between ___________________________ and the
     Warrantholder, and tenders herewith payment of the purchase price for such
     shares in full, together with all applicable transfer taxes, if any.

(2)  In exercising its rights to purchase the Series ___ Preferred Stock of
     ________________________, the undersigned hereby confirms and acknowledges
     the investment representations and warranties made in Section 10 of the
     Warrant Agreement.

(3)  Please issue a certificate or certificates representing said shares of
     Series ___ Preferred Stock in the name of the undersigned or in such other
     name as is specified below.


-----------------------------
(Name)

-----------------------------
(Address)


WARRANTHOLDER: COMDISCO, INC.

By:
       ------------------------

Title:
       ------------------------

Date:
       ------------------------


                                      -9-
<PAGE>   10
                                   EXHIBIT II

                           ACKNOWLEDGMENT OF EXERCISE

     The undersigned ___________________________, hereby acknowledges receipt
of the "Notice of Exercise" from Comdisco, Inc., to purchase ________ shares of
the Series ___ Preferred Stock of ___________________, pursuant to the terms of
the Warrant Agreement, and further acknowledges that _________ shares remain
subject to purchase under the terms of the Warrant Agreement.


                                       COMPANY:


                                       By:
                                              ------------------------

                                       Title:
                                              ------------------------

                                       Date:
                                              ------------------------



                                      -10-
<PAGE>   11
                                  EXHIBIT III

                                TRANSFER NOTICE

(TO TRANSFER OR ASSIGN THE FOREGOING WARRANT AGREEMENT, EXECUTE THIS FORM AND
SUPPLY REQUIRED INFORMATION. DO NOT USE THIS FORM TO PURCHASE SHARES.)

     FOR VALUE RECEIVED, the foregoing Warrant Agreement and all rights
evidenced thereby are hereby transferred and assigned to

_________________________________________________
(Please Print)

whose address is ________________________________

_________________________________________________

               Dated:____________________________

               Holder's Signature:_______________

               Holder's Address:_________________

               __________________________________

Signature Guaranteed: ___________________________

NOTE: The signature to this Transfer Notice must correspond with the name as it
      appears on the face of the Warrant Agreement, without alteration or
      enlargement or any change whatever. Officers of corporations and those
      acting in a fiduciary or other representative capacity should file proper
      evidence of authority to assign the foregoing Warrant Agreement.


                                      -11-