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                                                                   EXHIBIT 10.46

                               AGENCY AGREEMENT

THIS AGENCY AGREEMENT (the "Agreement") is entered into as of the 25th day of
July, 1997, to be effective as of the Effective Date, hereinafter defined,
between Concentric Network Corporation, a Florida corporation with offices at
10590 N. Tantau Avenue, Cupertino, CA 95014 ("CNC") and Williams Communications
Group, a Delaware corporation with offices at One Williams Center 17th Floor,
Tulsa, Oklahoma 74172 ("WCG").

In consideration of the mutual promises contained herein, CNC and WCG
(collectively the "PARTIES") agree as follows:

1.  Definitions.  For the purpose of this Agreement, the following terms and all
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terms defined elsewhere in this Agreement shall have the meanings so defined. A
term defined in the singular shall include the plural and vice versa when the
context so indicates.

"Customer" shall mean a school, government entity, individual, organization,
business, or institution that has contracted through WCG with CNC to purchase
Services, as delivered from CNC or as part of a value-added package offered by
WCG.

"Dispute Resolution Procedures" shall mean the dispute resolution procedures set
forth in Section 22 of this Agreement.

"Effective Date" shall be the Closing Date described in that certain Common
Stock and Warrant Purchase Agreement between the Parties entered into
concurrently with the execution of this Agreement.

"Services" shall mean CNC's products and services provided to WCG for which
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orders from CNC's Customers may be procured by WCG as a sales agent for CNC
under this Agreement, which Services shall be described in Exhibit A, as amended
                                                           ---------            
from time to time. Services shall include all current or future CNC products and
services, including without limitation all network and server/host based
products and services and all international products and services, that CNC
commercializes and makes generally available, except those which CNC is
contractually or legally prohibited from making available to WCG or those which
are reasonably determined by CNC to be technically infeasible for CNC..
"Services" shall include but not be limited to CNC RemoteLink,ConcentricHost
Shared Web Services and ConcentricHost Dedicated Co-location.  Subject to the
foregoing, updates to the current Exhibit A (includinginformation similar to
                                  ---------                                 
that which is provided in the current Exhibit A, such as Service descriptions,
costs to Customers and WCG's commissions) shall be made to this document as they
become available .  CNC will use commercially reasonable efforts to provide WCG
the ability to be a sales agent via CNC for Telecom Italia International network
services that are being deployed as part of the CNC/Telecom Italia relationship.

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"Subsidiary" shall mean any entity which WCG owns, directly or indirectly, fifty
percent (50%) or more of the equity securities or other equity interest granting
WCG voting rights exercisable in electing the management of such entity, but
only for so long as such ownership exists.

2.   Non-Exclusive CNC Sales Agent.
     ----------------------------- 

a) Subject to the terms contained herein, CNC hereby appoints WCG as CNC's non-
   exclusive sales agent for the sale of Services in accordance with the terms
   set forth in Exhibit B, and WCG hereby accepts such appointment.   By acting
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   as a sales agent, WCG shall not accept an order from a Customer for Services
   unless and until CNC has provided WCG with a written quote for such Services.
   Except as may be expressly set forth in CNC's quote for Services, WCG shall
   not have the authority to make any commitments whatsoever on behalf of CNC.

b) CNC warrants and represents that it is the owner of, or has sufficient rights
   to, the products that comprise the Services, including the software portions
   thereof, that it has the right to provide the Services to Customers, that it
   has the right to grant the agency rights stated in the preceding paragraph
   and that such grant does not conflict with any prior agency agreement or
   other agreement entered into by CNC, and CNC agrees that it shall not enter
   into any agency agreement or other agreement in the future which conflicts
   with this Agreement.

c) CNC and WCG shall meet no less frequently than once per quarter to discuss
   all Services that have been developed or are in the process of being
   developed by CNC. WCG will advise CNC of the current or developing Services
   for which WCG desires to serve as CNC's sales agent under the terms of this
   Agreement. For the designated Services that are immediately available, the
   Parties will attach to this Agreement information in the forms of Exhibit A
                                                                     ---------
   and Exhibit B with respect to those Services (including the applicable
       ---------
   financial accounting practices for each product) so that WCG can begin
   soliciting orders for those Services as CNC's agent. For the designated
   Services that are in the process of being developed, CNC will develop and
   attach to this Agreement information in the forms of Exhibit A and Exhibit B
                                                        ---------     ---------
   with respect to those Services as soon as the development of the subject
   Services allows, so that WCG can begin soliciting orders for those Services
   as CNC's agent immediately upon their availability to the public and without
   regard to the timing of the availability of those Services to other agents,
   provided, however, that CNC makes no representation or warranty that any
   Services in development will be completed, commercialized and made generally
   available. The availability of designated Services that are in the process of
   being developed are also subject to the absence of special requirements or
   modifications necessary for WCG. Without limitation as to other instances
   wherein the Dispute Resolution Procedures apply, if the Parties disagree as
   to which of CNC's products or services constitute "Services" under this
   Agreement and must therefore be offered on an agency basis to WCG hereunder,
   or if CNC otherwise refuses to offer to WCG the current or developing
   Services designated by WCG under this paragraph, or the Parties otherwise
   disagree as to either Party's compliance 

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   with the requirements of this paragraph, then the Parties agree to resolve
   such disputes in accordance with the Dispute Resolution Procedures.

3.        Scope of Agency; Employees. This Agreement appoints WCG as a non-
          --------------------------                                      
exclusive agent for the purposes expressly stated herein and does not appoint
WCG as CNC's general or special agent and does not create a joint venture or
apply to confer any status, power or authority upon WCG other than as expressly
set forth herein.  All persons employed by WCG to perform WCG's duties under
this Agreement are, and will remain, the employees and agents of WCG and are not
employees or agents of CNC.  WCG shall have sole responsibility for its
employees' supervision, direction and control.  Nothing contained in this
Agreement shall be construed to give either Party the power to direct and
control the day-to-day activities of the other.

4.        Commission.
          ---------- 

a) Most Favored Nation Status.  Commission rates, terms, and conditions of this
   --------------------------                                                  
   Agreement shall be provided to WCG on a "Most Favored Nation" basis. As used
   in this Agreement, "Most Favored Nation" status means that, taken as a whole
   and not individually, the commission rates, terms, and conditions offered to
   WCG under this Agreement are no less favorable than the commission rates,
   terms, and conditions, taken as a whole and not individually, provided to any
   other CNC agent. CNC will provide a nationally recognized independent third
   party auditor retained by WCG access upon fifteen (15) days prior notice, at
   WCG's expense, to other active agency agreements with CNC as a means by which
   WCG can ensure to its satisfaction that it is receiving "Most Favored Nation"
   status. If such auditor determines that another agent has more favorable
   commission rates, terms and conditions, then CNC will give WCG the
   opportunity to substitute all of the commission rates, terms and conditions
   that apply to such other agent for the commission rates, terms and conditions
   of this Agreement. . Remuneration will be in the form of credit going forward
   and will not be adjusted on past financial statements. Remuneration will
   applied if the material amount is greater than 10%.Said auditor shall be
   limited to one (1) audit per year for no longer than five (5) days and shall
   conduct the audit during normal business hours in a manner which will not
   unduly disrupt CNC's operations. The results of the audit shall be deemed
   Confidential Information.

b) Calculation of Commission.  Subject to the terms of Section 4(a), as the
   -------------------------             
   sole, exclusive and entire compensation for performing WCG's obligations
   under and during the term of this Agreement, CNC shall pay WCG a commission
   based on the billing of the Services sold by WCG in the percent specified and
   calculated according to Exhibit A attached hereto. Commission payments made
                           ---------       
   under this Agreement shall accrue on the first day of billing on an order
   received for the Services following the Effective Date. Commissions shall not
   be paid on non-CNC originated Services including without limitation local
   loops between Customer and CNC, 800 services, customer premises equipment,
   third party software, etc.

c) Payment of Commission.  The entire commission amount on an individual order
   ---------------------                                                      
   shall be payable to WCG thirty (30) days from the date CNC receives the
   initial payment from the 

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<PAGE>
 
   Customer for the Services purchased by the Customer. The commission amount
   will be based on the contract value of the agreement with the Customer as
   determined by CNC financial accounting practices as defined in Exhibits A and
   B. In the event that CNC extends its Customer agreement upon expiration, WCG
   shall continue to receive commission payments on such agreement as set forth
   herein. In the event the actual billings of a Customer are greater than the
   initial contract value due to variable usage charges and/or purchase of
   additional Services, WCG shall receive additional commissions on the
   additional billings at the rates set forth in Exhibit A. In the event that a
                                                 ---------
   Customer cancels its agreement prior to its term commitment, its billings are
   uncollectible, or adjustments are made to the billings then commission
   chargebacks to WCG will be made accordingly. Additional commission payments
   netted off by chargebacks will be performed two times per year. Payment of
   commissions shall be in United States dollars and shall be subject to all
   applicable governmental regulations and rulings, including withholding of any
   taxes required by law

d) Adjustments.  The commission rates, terms, and conditions of this Agreement
   -----------
   will be reviewed annually and adjusted, if necessary, to reflect WCG's "Most
   Favored Nation" status, current market conditions, and the economics of CNC's
   business. Without limitation as to other instances wherein the Dispute
   Resolution Procedures apply, if the Parties cannot agree on the items to be
   adjusted in accordance with the preceding sentence, then the Parties agree to
   resolve the dispute in accordance with the Dispute Resolution Procedures.

e) Taxes.  CNC shall be solely responsible to pay all applicable state or
   -----
   federal taxes, including state sales tax and use taxes, with respect to the
   Services. WCG shall be responsible for payment of taxes on income received by
   WCG hereunder.

5.        Quotas.  Subsequent to a reasonable amount of time following initial
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training, WCG shall assign quota's to the WCG sales force designated by WCG to
solicit orders for the Services covered herein.  WCG shall be solely responsible
for establishing quota levels and otherwise  administering the quota program.
The requirement of establishing quotas shall not be deemed to create or imply
any minimum order requirements by WCG hereunder, and the failure to meet any
quotas shall not constitute a breach of this Agreement or otherwise affect any
Party's rights or obligations hereunder.

6.        Prices and Terms of Sale.  CNC shall provide WCG with copies of its
          ------------------------                                           
current price lists, its availability schedules, and its standard terms and
conditions of sale, as established from time to time.  The standard terms and
conditions that apply to each Service shall be added to Exhibit B from time to
                                                        ---------             
time as they become available.   WCG shall quote to the Customers CNC's current
prices and shall sell the Services as delivered from CNC. If deviations are
required, WCG and CNC must mutually agree to accept such provisions.  CNC will
be paid for the Services based upon current or contracted price lists, from the
Customer.  CNC may alter the prices, availability schedules, and terms and
conditions for all new quotations upon thirty (30) days prior written notice to
WCG, such new pricing to take effect thirty (30) days after the date of such
written 

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<PAGE>
 
notice.  The corresponding sections of Exhibit A and Exhibit B shall be revised
                                       ---------     ---------         
accordingly. If a written quotation has been issued by CNC pursuant to Section
2.a.to a Customer, CNC shall honor that quote for the length of time as
specified by the quotation itself, provided such quotation has not expired.

7.        Training and Sales Support.  CNC will provide, at its expense, a
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designated point-of-contact for sales and/or technical support questions shared
by other channel organizations.  Additional sales and/or technical support will
be provided to WCG at WCG's expense and subject to mutual agreement.  However,
CNC will credit WCG 2% of the monthly revenue (net of commissions payable to
WCG) in excess of $500,000 towards the cost of these resources.  CNC will
provide initial training (e.g., one day of training per product unless
additional training is mutually agreed upon) on CNC Services as they are made
available to WCG.  WCG will reimburse CNC for its out-of-pocket expenses to
perform such training.  Such training will be designed to be a "train-the-
trainer" program, which will be held at a location to be mutually agreed to by
the Parties.  Additional training may be performed by CNC for WCG, at WCG's
request and expense, if both CNC and WCG deem it necessary.  From time-to-time,
and subject to mutual agreement, CNC may participate in cooperative sales calls
with WCG sales representatives for the purpose of enhancing the ability for WCG
representatives to become self-sufficient and productive in closing business on
behalf of CNC.  CNC will provide either camera-ready copy or , at WCG's expense,
quantities of sales promotion literature and materials.

8.        Acceptance; Performance by CNC.  All requests for quotations for
          ------------------------------                                  
Services shall be made in writing via E-mail, fax and/or letter by WCG to CNC
and subject to acceptance by CNC at its principal office currently located at
the address listed herein.  Upon acceptance by Customer of a quotation for
Services that has been accepted by CNC as described in the preceding sentence,
WCG shall provide a written commitment for all Services from the Customer.  This
shall be in the form of a Purchase Order ("P.O.") from the Customer and CNC's
Services Contract for Services for the Customer.  Such Services will not be
ordered until each P.O. and Services Agreement are received by CNC.  WCG shall
have no authority to make any acceptance or commitments to Customers, including
delivery dates, without CNC's prior written approval.  CNC shall have the sole
right of credit approval or credit refusal for the Customer in all cases.  CNC
shall perform all Services subscribed to by Customers in accordance the
applicable Services Contract, and shall be responsible for all facets of Service
delivery, revenue collection (customer billing), warranty fulfillment and
customer service.  CNC shall render all invoices directly to the Customer.  The
Customer shall make payments directly to CNC.  CNC shall undertake commercially
reasonable collection efforts for the Services sold through WCG hereunder.

9.        Trademarks, Service Marks, Logos and Tradenames.  CNC grants to WCG
          -----------------------------------------------                    
the non-exclusive, non-transferable right to use CNC's trademarks, service
marks, logos, and trade names that CNC may adopt from time to time ("CNC's
Trademarks") in connection with WCG's sale, advertisement or promotion of
Services, and shall provide WCG with such Trademarks within thirty (30) days of
the Effective Date.  During the term of this Agreement, WCG shall have the 

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<PAGE>
 
right to indicate to the public that it is an authorized sales agent of CNC's
Services and to advertise such Services under the Trademarks according to CNC
style guides referenced in Exhibit C. Nothing herein shall grant WCG any right,
title or interest in CNC's Trademarks. All representations of CNC's Trademarks
that WCG intends to use shall be exact copies of those used by CNC or shall
first be submitted to CNC for approval of design, color, and other details
thirty (30) days prior to duplication and/or distribution.

10.       Infringement Indemnity.  The following terms apply to any infringement
          ----------------------                                                
or claim alleging infringement by WCG in any country in which CNC provides the
Services of any patent, trademark, copyright, trade secret or other legally
protected proprietary right of any third party relating to the Services
(including WCG's use of the Trademarks in accordance with Section 9 hereof).
CNC shall indemnify, defend and hold harmless WCG, its owners, and the
directors, agents, officers and employees of each of them, from and against any
loss, damages, claim, suit or proceeding, expense or liability, including but
not limited to, costs of defense and reasonable attorney's fees, that may result
by reason of any such infringement or claim of infringement.  WCG shall notify
CNC promptly of any such claim of infringement for which CNC is responsible
hereunder and shall cooperate with CNC (at CNC's expense) in every reasonable
way to facilitate the defense of any such claim.  The indemnity obligations in
this Section shall survive the termination or expiration of this Agreement. This
Section sets forth CNC's entire liability and WCG's sole and  exclusive remedy
with respect to the infringement of intellectual property rights.

11.       Non-exclusive Agency Rights.  This Agreement does not grant CNC an
          ---------------------------                                       
exclusive privilege to furnish to WCG any or all of the types of products and
services which are the subject of this Agreement which WCG may require.  WCG
expressly reserves the right to serve as the agent for others for the sale of
products or services of the types which are the subject of this Agreement.

12.       Indemnification.  Each Party (the "Indemnifying Party") shall
          ---------------                                              
indemnify, defend and hold harmless the other Party, its owners, and the
directors, agents, officers, and employees of each of them (collectively, the
"Indemnified Party"), from and against any fine, penalty, loss, damages, claim,
suit or proceeding, expense or liability, including but not limited to, costs of
defense and reasonable attorney's fees, (i) for injury to or death of persons or
damage to or loss or destruction of property arising out of or resulting from or
in connection with the performance of this Agreement and caused by the acts or
omissions of Indemnifying Party, its contractors or agents, or an employee of
any of them, or (ii) arising out of or resulting from or in connection with any
material inaccuracy within, or breach of, a representation or warranty contained
in this Agreement.  The Indemnified Party shall notify the Indemnifying Party
promptly of any such claim for which Indemnifying Party is responsible hereunder
and shall cooperate with the Indemnifying Party (at the Indemnifying Party's
expense) in every reasonable way to facilitate the defense of any such claim.
The indemnity obligations under this Section shall survive the termination or
expiration of this Agreement.

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<PAGE>
 
13.       Facilities.  WCG shall provide itself with, and be solely responsible
          ----------                                                           
for, (i) such facilities, employees, and business organization, and (ii) such
permits, licenses, and other forms of clearance from governmental or regulatory
agencies, if any, as it deems necessary for the conduct of its business
operations in accordance with this Agreement.

14.       Books, Records, and Audits:  WCG and CNC shall maintain accurate,
          ---------------------------                                      
complete, and well organized records with respect to the Services subject to
this Agreement, at all times during this Agreement.  During the term of this
Agreement each Party  shall, upon fifteen (15) days written notice from the
other Party, make available to a nationally recognized independent third party
auditor retained by the requesting Party accurate books, records, and accounts
relating to the business of WCG and CNC with respect to the Services supplied by
CNC, for examination at the place of business where such books, records and
accounts are kept, during normal business hours and subject to the disclosing
party's reasonable security and confidentiality requirements  WCG shall also
maintain a record of any customer complaints regarding either the Services or
CNC and promptly forward to CNC the information regarding those complaints.
 
15.       Reporting.  Each Customer, total charges per Customer, and commission
          ---------                                                            
per Customer shall be detailed on the commission statement to be provided by CNC
to WCG on a monthly basis in a form suitable to both parties, written or
electronic.

16.       Publicity.  The Parties agree to cooperate in developing joint press
          ---------                                                           
releases from time-to-time related to activities and accomplishments
contemplated by this Agreement.  All press releases mentioning the other Party
must be approved in advance by both Parties prior to release.  Such approval
will be completed within three (3) business days and shall not be unreasonably
withheld.

17.       WCG Network Facilities; Peering Route Agreements; Telecom Italia.
          ---------------------------------------------------------------- 
a) For so long as this Agreement is in effect, CNC shall use its best reasonable
   efforts to groom traffic generated by WCG onto network facilities provided by
   WCG.

b) CNC shall contract with WCG so that WCG and its affiliates can participate in
   CNC's current and future private or public, peering or transit, or any other
   special arrangement established to provide Internet connectivity solutions.
   CNC shall provide said connectivity to WCG at cost, and will bill any direct
   incremental expenses separately including administrative, network
   engineering, & network operation costs, necessary to allow WCG such
   participation. WCG shall reimburse CNC for these costs & expenses.

c) CNC and WCG agree to exercise commercially reasonable efforts to establish a
   professional services, field services and other related services agreement
   between WCG and Telecom Italia for support of the Telecom Italia,
   International Network roll out. The parties further agree to propose the
   CNOP's organization as the entity to perform network management, network
   engineering, and network administration for the Telecom Italia International
   Network. Any cost benefits to CNOP's (e.g., due to increased economies of

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<PAGE>
 
   scale) from the Telecom Italia agreement will accrue to CNC in the form of a
   reduction in CNOP's costs to CNC. WCG's pricing for all of the services
   described in this paragraph shall be established by WCG at its sole
   discretion.

18.       Term.  This Agreement shall be for a period of two (2) years
          ----                                                        
commencing upon the Effective Date (the "Initial Period") subject to the right
of either party to terminate as provided in Section 19 (Termination).
Thereafter, this Agreement shall automatically renew for additional twelve (12)
month period(s) unless either party notifies the other of its intention to
terminate or modify this Agreement.  Such notification (the "Notice of
Nonrenewal") shall be provided in writing sixty (60) days prior to expiration of
the then current term.  Notwithstanding the foregoing, and unless (a) CNC
terminates this agreement for 'just cause' as defined in Section 19
(Termination), or (b) WCG's ownership of CNC's outstanding common or preferred
stock, as the case may be, falls below 5%, WCG shall have the right to renew
this Agreement under prices, terms, and conditions agreed to at the annual
review period described in Section 4.

19.       Termination.  Either party may terminate this Agreement upon the
          -----------                                                     
occurrence of "just cause" for termination, as defined below.  Termination for
just cause shall become effective immediately as of the date on which such just
cause occurred (which date, in the case of paragraph (a) below, shall be day
following the end of the referenced cure period), unless otherwise provided for
in this Agreement.  Just cause for termination by a Party shall consist of the
following:

a) Failure to Comply with Obligations.  Failure by the other Party (the
   ----------------------------------                                  
"Noncomplying Party") to comply with any of its obligations hereunder within
thirty (30) calendar days from its receipt of written notice to that effect from
the other Party or, if the failure to comply is of such a nature that it cannot
reasonably be expected to be remedied within thirty (30) days, the Noncomplying
Party's failure to exert substantial efforts to correct such failure within such
thirty-day time period.

b) Dissolution.  Dissolution or any assignment by the other Party for the
   -----------
benefit of its creditors, the appointment of a receiver for, or any execution
levied upon, all or substantially all of the other Party's business or assets,
or the filing of any petition for voluntary or involuntary bankruptcy or similar
proceeding for or against the other Party.

The termination of this Agreement shall not affect any accrued rights or
obligations of either Party as of the effective date of such termination, nor
shall it affect any rights or obligations of either Party which are intended by
the Parties to survive any such termination, including without limitation those
contained in Section 10 (Infringement Indemnity), Section 12 (Indemnification),
Section 21 (Confidential Information), and CNC's obligations to pay commissions
pursuant to Section 4.

20.       Transition Period. In the event this Agreement is terminated by WCG
          -----------------                                                  
for "just cause", then , at WCG's request, CNC will waive any remaining term
commitments for CNC Customer's 

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<PAGE>
 
acquired through WCG under this Agreement in order to enable WCG to migrate
those Customers to WCG services in a timely manner. The time period between the
date of a Notice of Nonrenewal and the end of the term in which such notice is
provided shall hereinafter be referred to as the "Transition Period". CNC and
WCG agree to utilize commercially reasonable efforts to effectuate a smooth and
orderly change during the Transition Period in order to satisfy the best
interests of CNC's Customers.
 
21.       Confidential Information:  Each party agrees to maintain all
          -------------------------                                   
Confidential Information (as hereinafter defined) in confidence to the same
extent that it protects its own similar Confidential Information and to use such
Confidential Information only as permitted under this Agreement. For purposes of
this Agreement "Confidential Information" shall mean information including,
without limitation, computer programs, code, algorithms, names and expertise of
employees and consultants, know-how, formulas, processes, ideas, inventions
(whether patentable or not), schematics and other technical, business, financial
and product development plans, forecasts, strategies and information marked
"Confidential", or if disclosed verbally, is identified as confidential at the
time of disclosure and reduced to a confidential writing within thirty (30) days
after such disclosure.  Each party agrees to take all reasonable precautions to
prevent any unauthorized disclosure or use of Confidential Information
including, without limitation, disclosing Confidential Information only to its
directors, officers, employees and/or professional advisors (a) with a need to
know to further permitted uses of such information; (b) who are parties to
appropriate agreements sufficient to comply with this Section; and (c) who are
informed of the nondisclosure/ non-use obligations imposed by this Section; and
both parties shall take appropriate steps to implement and enforce such non-
disclosure/non-use obligations. The foregoing restrictions on disclosure and use
shall survive for three (3) years following termination of this Agreement but
shall not apply with respect to any Confidential Information which:  (i) was or
becomes publicly known through no fault of the receiving party; (ii) was
rightfully known or becomes rightfully known to the receiving party without
confidential or proprietary restriction from a source other than the disclosing
party; (iii) is independently developed by the receiving party without the
participation of individuals who have had access to the Confidential
Information; (iv) is approved by the disclosing party for disclosure without
restriction in a written document which is signed by a duly authorized officer
of such disclosing party; or (v) the receiving party is legally compelled to
disclose; provided, however, that prior to any such compelled disclosure, the
receiving party will (a) assert the privileged and confidential nature of the
Confidential Information against the third party seeking disclosure and (b)
cooperate fully with the disclosing party in protecting against any such
disclosure and/or obtaining a protective order narrowing the scope of such
disclosure and/or use of the Confidential Information. In the event that such
protection against disclosure is not obtained, the receiving party will be
entitled to disclose the Confidential Information, but only as, and to the
extent, necessary to legally comply with such compelled disclosure. Each of the
Parties hereto agrees not to disclose to any third party the terms of this
Agreement without the prior written consent of the other party hereto, except to
advisors, investors and others on a need-to-know basis under circumstances that
reasonably ensure the confidentiality thereof, or to the extent required by law.

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<PAGE>
 
23.       LIMITATION ON LIABILITY.   IN NO EVENT SHALL EITHER PARTY BE LIABLE TO
          -----------------------                                               
THE OTHER OR TO ANY OTHER ENTITY FOR ANY SPECIAL, CONSEQUENTIAL, INCIDENTAL, OR
INDIRECT DAMAGES, HOWEVER CAUSED ON ANY THEORY OF LIABILITY.  NOTWITHSTANDING
ANYTHING HEREIN TO THE CONTRARY, NEITHER PARTY'S LIABILITY TO TO THE OTHER SHALL
IN ANY EVENT EXCEED THE AMOUNT OF AGGREGATE NET REVENUE RECEIVED BY CNC LESS WCG
COMMISSIONS FROM CNC CUSTOMERS PROCURED BY WCG AS A SALES AGENT FOR CNC DURING
THE PREVIOUS TWELVE (12) MONTHS; PROVIDED, HOWEVER, THAT THE FOREGOING
LIMITATION SHALL NOT APPLY TO LIMIT LIABILITY AMOUNTS ARISING FROM SECTIONS 10
AND 12
 

24.       Governing Law and Jurisdiction.  This Agreement shall be governed by
          ------------------------------                                      
and construed under the laws of the state of California, without reference to
conflict of law principles.
 
25.       Entire Agreement.  This Agreement, including any Exhibits and
          ----------------                                             
attachments that may be added from time to time, sets forth the entire agreement
and understanding of the parties relating to the subject matter herein and
merges all prior discussions between them.  No modification of or amendment to
this Agreement, nor any waiver of any rights under this Agreement, shall be
effective unless in writing signed by the party to be charged.
 
26.       Notices.  Any notice required or permitted by this Agreement shall be
          -------                                                              
in writing and shall be deemed given (a) upon personal delivery, (b) on the
third day following mailing sent by registered or certified mail, return receipt
requested, postage prepaid, (c) upon confirmed delivery by means of a nationally
recognized overnight courier service or (d) upon confirmed transmission of
facsimile, addressed to the other party at the address shown at the beginning of
this Agreement or at such other address for which such party gives notice
hereunder.
 
27.       Force Majeure. Neither Party shall be deemed in default of this
          -------------                                                  
Agreement to the extent that any delay or failure in the performance of its
obligations results from an Act of God, act of civil or military authority,
embargo, epidemic, war, riot, insurrection, fire, explosion, earthquake, flood,
unusually severe weather conditions or any other cause beyond such Party's
reasonable control which cannot be overcome by due diligence, provided that such
Party (the "Affected Party") gives the other Party (the "Unaffected Party')
prompt notice of such condition.

If either Party's performance is so excused, the Unaffected Party may either:

a) require the Affected Party to continue performance as soon as practicable
   after the delay has ended; or

b) terminate without penalty any affected obligation (or portion thereof) of the
   Unaffected Party hereunder by giving written notice to the Affected Party.

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<PAGE>
 
The Unaffected Party may select option (a) as to certain obligations hereunder
or parts thereof and option (b) as to other affected obligations or parts
thereof.  In the absence of notice of selection of any option with respect to a
particular affected obligation, option (a) will be deemed selected.

28.       Non-Assignability and Binding Effect.  Neither Party shall assign its
          ------------------------------------                                 
rights or delegate its duties under this Agreement without the prior written
consent of the other Party, which consent shall not be unreasonably withheld.
Notwithstanding the foregoing a. WCG may, with written notice to CNC, assign
this Agreement to a Subsidiary; and

CNC may, with written notice to WCG, assign this Agreement to an entity that is
formed for CNC's reincorporation as a Delaware corporation.  Subject to the
foregoing, this Agreement shall be binding upon and inure to the benefit of the
parties hereto, their successors and assigns.

 
29.       Legal Expenses.  The prevailing party in any legal action brought by
          --------------                                                      
one Party against the other and arising out of this Agreement shall be entitled
to reimbursement for its expenses, including court costs and reasonable
attorneys' fees.

30.       Counterparts.  This Agreement may be executed in two or more
          ------------                                                
counterparts, each of which shall be deemed an original.

31.       Headings.  The section headings contained in this Agreement are for
          --------                                                           
reference purposes only and shall not affect in any way the meaning or
interpretation of this Agreement.

32.       Severability.  If any provision or part of a provision of this
          ------------                                                  
Agreement shall be invalid or unenforceable, such invalidity or unenforceability
shall not invalidate or render unenforceable the entire Agreement or provision
but rather the entire Agreement or provision shall be construed as if not
containing the particular invalid or unenforceable provision or portion thereof,
and the rights and obligations of CNC and WCG shall be construed and enforced
accordingly.

33.       Resolution of Disagreements Between Parties.  No Party to this
          -------------------------------------------                   
Agreement shall be entitled to take legal action with respect to any dispute
relating hereto until it has complied in good faith with the following
alternative dispute resolution procedures.  If a dispute, claim or controversy
arises with respect to or relates to any Section of this Agreement, then the
following dispute resolution procedures shall govern the parties' conduct:

       a) The Parties shall attempt promptly and in good faith to resolve any
          dispute arising out of or relating to this Agreement through
          negotiations between representatives who have authority to settle the
          controversy. Either Party may give the other Party written notice of
          any such dispute not resolved in the normal course of business.
          Negotiations extending ten (10) days after the disputing Party's
          notice shall be 

                                       11
<PAGE>
 
          deemed at an impasse, unless otherwise agreed by the Parties. If a
          negotiator intends to be accompanied at a meeting by an attorney, the
          other negotiator(s) shall be given at least two (2) working days
          notice of such intention and may also be accompanied by an attorney.
          All negotiations pursuant to this clause are confidential and shall be
          treated as compromise and settlement negotiations for purposes of the
          Federal and State Rules of Evidence.

       b) If a dispute is at an impasse (i.e., it has not been resolved within
          ten (10) days of the disputing Party's notice), the dispute shall be
          settled by arbitration in a mutually convenient location, in
          accordance with the Commercial Arbitration Rules of the American
          Arbitration Association in effect on the date that such notice is
          given. If the parties are unable to agree on a single arbitrator
          within ten (10) days from the date of an impasse as set forth in
          Subsection (a), then the CNC and WCG shall each select one arbitrator
          within ten (10) days and the two (2) arbitrators shall select a third
          arbitrator within ten (10) days. If a Party does not designate an
          arbitrator or if the two appointed arbitrators cannot agree on the
          final arbitrator within the foregoing time periods, then the American
          Arbitration Association shall select the arbitrator(s) upon request of
          either Party. The decision of the arbitrator(s) shall be final and
          binding upon the parties and shall include written findings of law and
          fact, and judgment may be obtained thereon by either Party in a court
          of competent jurisdiction. Each Party shall bear the cost of preparing
          and presenting its own case. The cost of the arbitration, including
          the fees and expenses of the arbitrator(s), shall be shared equally by
          the Parties hereto unless the award otherwise provides. The
          arbitrator(s) shall be instructed by the Parties to establish
          procedures such that a decision can be rendered by the arbitrator(s)
          within sixty (60) days of the date that the last arbitrator is
          selected.

       c) The obligation herein to arbitrate shall not be binding upon either
          Party with respect to requests for preliminary injunctions, temporary
          restraining orders, specific performance or other procedures in a
          court of competent jurisdiction to obtain interim relief when deemed
          necessary by such court to preserve the status quo or prevent
          irreparable injury pending resolution by arbitration of the actual
          dispute.

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

 
CONCENTRIC NETWORK CORPORATION("CNC")    WILLIAMS COMMUNICATIONS GROUP, INC.
                                         ("WCG")

By: /s/Henry R. Nothhaft                By: /s/Miller Williams
    ---------------------------------       --------------------------------
Printed Name:  Henry R. Nothhaft        Printed Name:  Miller Williams
              -----------------------                  ---------------------

                                       12
<PAGE>
 
Title: President and CEO                Title: Senior Vice President
       ------------------------------          ----------------------------- 

                                       13
<PAGE>
 
                                   EXHIBIT A
                                   ---------
                           COMMISSION PRICING FOR WCG
<TABLE>
<CAPTION>
 
REMOTELINK/TM/
------------------------------------------------------------------------------------------------------------------------------------

NON-RECURRING CHARGES (NRC)  DESCRIPTION                                LIST PRICE              COMMISSIONABLE
------------------------------------------------------------------------------------------------------------------------------------

<S>                          <C>                                        <C>                     <C>
CPE router                   Bay Networks AN                            $  1,895                NO
(optional, customer may      Router
 supply if desired)          2 ethernet ports,
                             1 sync port

CSU                          Racal 5311 T-1 CSU                         $   995                 NO
(REQUIRED, FOR EFFECTIVE
 CIRCUIT MAINTENANCE AND
 TROUBLESHOOTING)

DAF Installation & Setup     Installation of telco circuit from         $ 3,000                 YES
                             Concentric to customer site, provisioning 
                             of service, and onsite installation and 
                             testing of connectivity through CSU and 
                             router

NT Server                    Compaq Proliant 800 6/180                  $10,000                 NO
(optional, customer may      180 megahertz Pentium Pro 4.6
 supply if desired)          gigabyte hard disk,
                             64 megabytes RAM, 10BaseT ethernet card, 
                             8x CD-ROM, NT 4.0, 5 user license

RADIUS Server Software       Steel Belted RADIUS Server                 $ 4,000                 NO
(optional, customer may      software, for NT or Netware
 supply if desired)          (specify which platform is desired)

On Site Installation         1 SE day, onsite installation of           $1,250 +                NO
support and Network          RADIUS server, training on use,            actual travel
Management Training Course   and training on use of ConcentricView.     expenses
                             Oriented to customer network
                             management personnel

End User Training Course     1 SE day, onsite training class            $1,250 +                NO
                             oriented to end users- how to set          actual travel
                             up access to RemoteLink, and               expenses
                             use the service

Help Desk Training Course    1 day training course for customers        $500 per                NO
                             help desk personnel, training them to      attendee,class 
                             perform 1/st/ tier support of end          given in our
                             users dialing in through Concentric.       Saginaw, Michigan
                             This is oriented to customers              support center
                             wanting to do 1/st/ tier support 
                             themselves.

MONTHLY RECURRING CHARGES    DESCRIPTION                                PRICE
 (MRC)
RemoteLink/TM/ usage price   usage charges for remote user              see table below         YES
                             activity

Monthly DAF fees             Charge for the FullChannel/TM/,            see table below         YES
                             FlexChannel/TM/, or LEC Frame Relay
                             dedicated connection to Concentric

Tier 1 customer support,     Concentric help desk support, 3            $1/minute of use,        NO
 Virtual CSR,                minute average speed to answer             actual amounts
3 minute ASA                 using virtual CSR's                        billed monthly- SEE
(Fixed response time                                                    BELOW FOR ADDITIONAL
 option, costs will vary)                                               IMPORTANT INFORMATION

Tier 1 customer support,     Concentric help desk support, 1            $3/minute of             NO
 Virtual CSR,                minute average speed to answer             use, actual
1 minute ASA                 using virtual CSR's                        amounts billed
(Fixed response time                                                    monthly- SEE BELOW 
 option, costs will vary)                                               FOR ADDITIONAL 
                                                                        IMPORTANT INFORMATION

</TABLE> 

                                       14
<PAGE>
 
<TABLE> 
<CAPTION> 
 
------------------------------------------------------------------------------------------------------------------------------------

<S>                          <C>                                        <C>              
Tier 1 customer support,     Concentric help desk support,              $300 per shift,          NO
1 shift seat                 one physical CSR, 8 hrs.                   $1,500 per week, 
(Fixed cost  option,         per day, 5 days per week,                  $78,000 per year
 response times to answer    annual basis                               billed monthly- SEE
 users will vary depending                                              BELOW FOR ADDITIONAL
 on call load and peak                                                  IMPORTANT INFORMATION
 periods)                                                               

</TABLE>

                                       15
<PAGE>
 
<TABLE>
<CAPTION>
 
REMOTELINK USAGE PRICING*
------------------------------------------------------------------------------------------------------------------------------------

NUMBER OF HOURS CONSUMED       DOLLARS PER         18% WCG        DOLLARS PER           18% WCG      DOLLARS PER          18% WCG
 PER MONTH                     HOUR: NO            COMMISSION     HOUR:                 COMMISSION   HOUR:                COMMISSION

                               CONTRACT TERM                      1 YEAR CONTRACT                    2 YEAR CONTRACT
                               COMMITMENT                         COMMITMENT                         COMMITMENT
------------------------------------------------------------------------------------------------------------------------------------

<S>                          <C>               <C>               <C>               <C>              <C>              <C>
0 - 25,000                              $2.55             $ .46           $  2.30           $  .41          $  2.17           $  .39

25,001 - 50,000                         $2.42             $ .44           $  2.19           $  .39          $  2.07           $  .37

50,001 - 75,000                         $2.35             $ .42           $  2.12           $  .38          $  1.99           $  .36

75,001 - 100,000                        $2.30             $ .41           $  2.07           $  .37          $  1.94           $  .35

100,001 - 125,000                       $2.27             $.405           $  2.04           $ .365          $  1.91           $  .34

125,000 +                               $2.24             $ .40           $  2.01           $  .36          $  1.88           $ .335

MINIMUM MONTHLY PAYMENT                 NONE               NA             $10,000           $1,800          $10,000           $1,800

------------------------------------------------------------------------------------------------------------------------------------

</TABLE>
   *PRICES ARE BASED UPON LOCAL (I.E. NO TOLL CHARGE) ANALOG DIAL-UP ACCESS.
   1-800 ANALOG DIAL-UP ACCESS IS BILLED AT THE FLAT RATE OF $6 PER HOUR.

REMOTELINK DAF MONTHLY RECURRING CHARGES

Several options are available for connection of the customers network to
Concentric.  These options, and their pricing, are listed below.  In addition to
the charges noted, there will be a local loop fee from the Local Exchange
Carrier, which is variable depending on distance between their POP and the
Customer data center.  Call for a specific local loop quote from Concentric.

FullChannel/TM/ T1 Usage Pricing

FullChannel/TM/ T1 offers a full T1 (1.54 Mbps) of bandwidth over a non-shared,
non-fractional leased line. Monthly billing is based on traffic samples taken
every five minutes, 24 hours a day, 7 days a week. Your monthly charge is
determined by the average of these samples.

<TABLE>
<CAPTION>
----------------------------------------------------------------------
AVERAGE USAGE LEVEL                 MONTHLY FEE(1)  15% WCG COMMISSION
----------------------------------------------------------------------
<S>                                 <C>             <C>
-64Kbps                               $1,095.00                $164.25
64-128Kbps                            $1,595.00                $239.25
128-256Kbps                           $2,095.00                $314.25
256-384Kbps                           $2,395.00                $359.25
over 384Kbps                          $2,695.00                $404.25
</TABLE> 

FullChannel T1 Protected Pricing

Protected pricing is not usage based.  It is simply billed at the flat monthly
rate shown, and requires a RemoteLink contract term of 1 year or more.

<TABLE>
<CAPTION>
---------------------------------------------------------
SUSTAINED LEVEL           MONTHLY FEE  15% WCG COMMISSION
---------------------------------------------------------
<S>                       <C>          <C>
64Kbps to over 384Kbps      $2,095.00             $314.25
</TABLE>

                                       16
<PAGE>
 
FlexChannel/TM/ T1 Pricing
FlexChannel/TM/ T1 offers you a predetermined level (128Kbps - 512Kbps) of
bandwidth on a fractional T-1 line, for a fixed monthly fee. You can always
upgrade to the full T1 later.

<TABLE>
<CAPTION>
-----------------------------------------------------------------
FRACTIONAL T1 BANDWIDTH        MONTHLY FEE(1)  15% WCG COMMISSION
-----------------------------------------------------------------
<S>                            <C>             <C>
128Kbps                          $  895.00     $134.25
256Kbps                          $1,295.00     $194.25
384Kbps                          $1,595.00     $239.25
512Kbps                          $1,895.00     $284.25

</TABLE> 

LEC Frame Relay Pricing (2)

LEC Frame Relay service offers reliable, cost-effective Internet access from
56Kbps - 512Kbps* at a lower cost than traditional leased lines. While we can't
guarantee the throughput of the LEC's frame cloud, we will not over subscribe
the entrance facility. The committed information rate (CIR) over the Concentric
Network is guaranteed.

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
FRAME RELAY CIRCUIT/CIR        MONTHLY FEE(1)  15% WCG COMMISSION
--------------------------------------------------------------------------------
<S>                            <C>             <C>
56Kbps/32Kbps                    $  395.00     $ 59.25
128Kbps/64Kbps                   $  795.00     $119.25
256Kbps/128Kbps                  $  995.00     $149.25
512Kbps/256Kbps                  $1,095.00     $164.25
</TABLE> 
(1) Monthly billing based on average usage.

(2) Offer varies by region, call for exact quote.

<TABLE> 
<CAPTION> 


CONCENTRICHOST
--------------
--------------------------------------------------------------------------------------------------
PRODUCT NAME        DESCRIPTION         NUMBER OF      WEB              MONTHLY         15% 
                                        EMAIL          SITE             RECURRING       WCG
                                        ACCTS          STORAGE          CHARGES         COMMISSION
--------------------------------------------------------------------------------------------------
<S>                 <C>                 <C>            <C>              <C>             <C> 
HomeOffice          Shared service      5              5MB              $29.95          $4.49
                    with customized
                    sub-domain

SmallBusiness       Shared service      5              10MB             $39.95          $5.99
                    with full domain
                    name service and
                    dial-up account

Premium             Shared service      10             1000MB           $59.95          $8.99
                    with full domain
                    name service and
                    dedicated IP 
                    address
</TABLE>

ConcentricHost is a high performance shared web server service that give the End
User an inexpensive web presence.  All Web servers reside at one of CNC's data
centers.

                                       17
<PAGE>
 
<TABLE>
<CAPTION>

CONCENTRICHOST-COLOCATION
-------------------------
-----------------------------------------------------------------------------------------------------------------
DESCRIPTION                             BANDWIDTH               MONTHLY RECURRING CHARGES (1)  15% WCG COMMISSION
-----------------------------------------------------------------------------------------------------------------
<S>                                     <C>             <C>                            <C>
Server on shared Ethernet segment       1Mbps                   $1,500                            $255
Server on shared Ethernet segment       2Mbps                   $2,500                            $375
Server on shared Ethernet segment       4Mbps                   $4,000                            $600
Server on dedicated Ethernet segment    10Mbps                  $6,000                            $900
Install & Setup                         Per server              $1,000                            $150
Additional rack space                   8" x 19" Space          $  500                            $ 75
Installation of extra rack space                                $500 - NRC                        $ 75
Engineering assistance                  Scheduled               $100/Hr.                          NA
Engineering assistance                  Emergency               $250/Hr.                          NA

</TABLE>

ConcentricHost-Colocation is a service that allows CNC customers to put their
own dedicated Web servers in one of our data centers.  The following is a list
of CNC co-location services that are currently offered.  Each connection comes
with an 8" rack space based Future services are being defined and will be
introduced as they are developed.

CUSTOMER SUPPORT

FIRST TIER END USER SUPPORT

Concentric offers two types of First Tier End User Support.  Customer may select
from the following two options.

Shift Seat Customer Support Representative (CSR):
------------------------------------------------
- One (1) Support Representative Shift  Increment  is $300.00 . A Support
Representative Shift Increment  is an eight (8) hour increment of time, provided
for 5 out of 7 days in each week, not including Holidays, during which one (1)
Customer Support Representative will be dedicated to answering support calls of
the Customer's Customer End Users.

- The minimum purchase amount is one (1) shift for a five (5) day week for one
year for $78,000.00

- Shift seats may be purchased in 8 or greater hour increments, and will be
prorated.  Start of shift times may be supplied by Customer according to their
requirements.

- When shift seats are purchased, there are no Average Speed to Answer (ASA)
guarantees.  The actual time to answer will vary depending on incoming call
traffic, and peak flows.

Virtual Customer Support Representative (CSR):
---------------------------------------------
- Utilizes the Concentric pool of CSR's

- Automatic Call Distributor system prioritizes incoming calls to deliver a
guaranteed ASA*

- ASA guaranteed at 3 minutes is billed out at $1 per actual minute used

- ASA guaranteed at 1 minute is billed out at $3 per actual minute used

IT IS IMPORTANT TO NOTE THAT BY PURCHASING SHIFT SEATS, COSTS ARE FIXED, BUT
RESPONSE TIMES WILL VARY.  BY UTILIZING THE VIRTUAL CSR OPTION, RESPONSE TIMES
ARE FIXED, BUT COSTS WILL VARY.

SECOND TIER END USER SUPPORT

Included at no extra charge for so long as Customer is purchasing Concentric
RemoteLink.  Second Tier support is provided by 

                                       18
<PAGE>
 
Concentric to up to five (5) identified Customer help desk personnel.

                                       19
<PAGE>
 
                                   EXHIBIT B
                                   ---------

                            DESCRIPTION OF SERVICES
     with attachments for each Service setting forth the terms, conditions,
             service level agreements and pricing relating thereto
                     CNC REMOTELINK/TM/ SERVICES AGREEMENT
                                        
          This agreement ("Agreement") is made  and entered into on this  ___
day of _______,  199  ("Effective Date") by and between Concentric Network
                    _ 
Corporation ("Concentric"), a Florida corporation with a principal place of
business at 10590 N. Tantau Ave., Cupertino CA 95014, and
________________________( "Customer") a ______________ corporation with a
principal place of business at ________________________________.

          WHEREAS, Customer would like to outsource the operation of remote
access to Customer's LANs and Intranets;

          WHEREAS, Customer wishes to obtain remote access service from
Concentric, and Concentric wishes to provide this service to Customer,

          NOW THEREFORE, the parties agree as follows:

1.0       DEFINITIONS

          1.1  "CityFind" shall mean the object code of the software application
          which allows Customer End Users to locate their nearest Concentric
          Point of Presence.

          1.2  "Concentric Network" shall mean the collection of network
          equipment, access lines, data centers and network management tools
          which Concentric operates to deliver network services to customers.

          1.3  "Concentric RemoteLink/TM/" shall mean the network service
          offered by Concentric that allows Customer End Users to access the
          Customer's internal corporate network, local area network(s) or
          intranet via a connection from the Concentric Network to the
          Customer's home gateway.

          1.4  "ConcentricView/TM/" shall mean the web-based desktop network
          monitoring application developed by Concentric, for the purpose of
          monitoring vital network data on the performance of the Concentric
          Network such as user activity and router and firewall statistics.

          1.5  "Customer End User(s)" shall mean those employees, consultants,
          contractors, and other individuals or entities outside the Customer's
          firewall that the Customer has

                                       20
<PAGE>
 
          authorized to use personal computers running Windows to use the
          Concentric RemoteLink/TM/ service and who have accepted the end user
          license agreement accompanying the CityFind software, but only so long
          as Customer has authorized such employees, consultants, contractors,
          and other individuals or entities.

          1.6  "DAF" shall mean the dedicated access facilities and provisioning
          selected by Customer to connect the Customer's home gateway to the
          Concentric Network.

          1.7  "Fees" shall mean all amounts due hereunder including amounts due
          for One Time Items and Monthly Recurring Items as set forth in Exhibit
          A, and as such items are selected by Customer in Exhibit C.

          1.8  "First Tier End User Support" shall mean the provision of direct
          telephone based support to Customer End Users for connectivity
          problems directly associated with connecting a personal computer with
          an analog modem running Windows to the Concentric Network. First Tier
          End User Support includes troubleshooting to verify that data
          transmitted by the user is being delivered to the Concentric router
          interface which provides connection to the Customer network.

          1.9  "RADIUS Server" shall mean a server that contains a database
          which operates per the Remote Authentication Dial In User Service
          protocol as defined in IETF RFC 2058.

          1.10 "Second Tier End User Support" shall mean the provision of direct
          telephone based support by Concentric to up to five (5) designated
          members of the in-house support desk of Customer so that the in-house
          support desk of Customer can directly support Customer End Users in
          connectivity to the Concentric RemoteLink/TM/ service. Second Tier End
          User Support does not include direct telephone based support of end
          users.

          1.11 "Term" shall mean the period during which this Agreement is in
          effect as determined by the Customer's selection in Exhibit C.

2.0       NETWORK SERVICES PROVIDED BY CONCENTRIC

          2.1  Subject  to the terms and conditions herein, Concentric shall
          make available access to the Concentric Network via the Concentric
          RemoteLink service to Customer End Users using a personal computer
          running Windows equipped with an analog modem with a PPP connection
          over a local dial-up telephone access line.

          2.2  Subject  to the terms and conditions herein, Concentric will
          deliver IP data network traffic from the Customer End User's personal
          computer through the dial up access portion of the Concentric Network
          (at speeds currently up to 28.8 kbps), to the 

                                       21
<PAGE>
 
          router or termination equipment at the Customer's home gateway.
          Concentric will interconnect the Concentric Network to the Customer's
          home gateway via the DAF.

          2.3  Concentric shall use commercially reasonable efforts to operate
          and monitor the Concentric Network on a seven (7) days a week, twenty-
          four (24) hours a day, three hundred sixty-five (365) days a year
          basis, with scheduled maintenance downtimes.

          2.4  Concentric will deliver ConcentricView /TM/ to Customer upon
          installation of the DAF.

          2.5  Concentric Network Corporation guarantees throughput and latency
          for the dedicated access connection to the Concentric Network. Latency
          is guaranteed to be 200 milliseconds or less between any two points on
          the Concentric Network. Throughput is guaranteed at the data rate
          selected for the DAF connection.



3.0       LICENSE GRANT AND RESTRICTIONS

          3.1  Subject  to the terms and conditions herein, Concentric hereby
          grants and Customer hereby accepts a nonexclusive, nontransferable
          license to: (a) use the CityFind software in accordance with the
          license grant contained in the end user license agreement that
          accompanies the CityFind software; (b) reproduce, without change, only
          that quantity of the CityFind software necessary for Customer End
          Users and members of Customer's in house support desk; and (c)
          distribute the CityFind software to Customer End Users and members of
          Customer's in house support desk.

          3.2  Subject to the terms and conditions herein, Concentric hereby
          grants and Customer hereby accepts a nonexclusive, nontransferable
          license to access the server(s) on the Concentric Network containing
          ConcentricView and use ConcentricView solely for Customer's internal
          use in monitoring Customer End User usage by members of Customer's in
          house support desk and network system administrator(s).

          3.3  Customer's license to use the NT Server software and/or RADIUS
          Server software, and any other third party software, if Customer had
          elected to obtain such software from Concentric, is as set forth in
          the license agreement accompanying such software.

          3.4  Customer agrees not to alter, amend, remove or disable any
          proprietary notice, legend or license agreement contained in or on any
          software provided to Customer by Concentric. Customer agrees not to
          reproduce (except as expressly permitted herein), modify, translate,
          transform, de-compile, reverse engineer, disassemble, or otherwise
          determine or attempt to determine source code from the executable code
          of, the CityFind 

                                       22
<PAGE>
 
          or to permit or authorize a third party to do so. Title to the
          CityFind software, ConcentricView, and all related technical know-how
          and intellectual property rights therein and in the Concentric Network
          and Concentric RemoteLink are and shall remain the exclusive property
          of Concentric and/or its suppliers. Customer shall not take any action
          to jeopardize, limit or interfere in any manner with Concentric and
          its suppliers' ownership of and rights with respect to the CityFind
          software, ConcentricView, the Concentric Network and Concentric
          RemoteLink.

          3.5  Customer shall use commercially reasonable efforts to: (a)
          enforce each end user license agreement for CityFind with each
          Customer End User; (b) require the return or destruction of the
          CityFind software from a Customer End User when no longer authorized
          by Customer to use Concentric RemoteLink (e.g. employee leaves
          Customer's employment, consultant completes assignment); and (c)
          cooperate with Concentric to prevent or stop the unauthorized use,
          reproduction or distribution of the CityFind software.

          3.6  Customer shall fully comply with all then current applicable
          laws, rules and regulations relating to the export of technical data,
          including, but not limited to any regulations of the United States
          Office of Export Administration and other applicable governmental
          agencies. Customer hereby assures Concentric that it will not export
          directly or indirectly (including via remote access, FTP or other
          means) any part of CityFind or technical data to any country for which
          a validated license is required under US law without first obtaining a
          validated license.

4.0       INSTALLATION AND SUPPORT

          4.1  Concentric and Customer will cooperate and use commercially
          reasonable efforts to do all things necessary to perform and complete
          the implementation plan tasks set forth in Exhibit B within ninety
          (90) days of the Effective Date.

          4.2  Unless Customer selects and pays for Concentric to provide First
          Tier End User Support, Customer shall be solely responsible for
          providing First Tier End User Support. If Customer selects and pays
          for Concentric to provide First Tier End User Support, and Customer
          supplies Concentric with a RADIUS test account, Concentric shall also
          provide troubleshooting on verification of the operational status of
          the RADIUS server as appropriate.

          4.3  If Customer is providing First Tier End User Support, Customer
          must select and pay for the Help Desk Training Course described in
          Exhibit A. In the event that Concentric's Support Center is being
          contacted by Customer End Users for First Tier End User Support,
          Customer agrees to: (a) cooperate with Concentric to minimize such
          contact; and (b) pay Concentric its then current support charges for
          support provided by Concentric to such Customer End Users.

                                       23
<PAGE>
 
          4.4  Concentric shall provide Second Tier End User Support for so long
          as Customer is paying Concentric for the Concentric RemoteLink
          service.

5.0       CUSTOMER RESPONSIBILITIES

          5.1  Customer is solely responsible for maintaining the integrity and
          ongoing operation of the RADIUS Server which the Concentric Network
          queries for the purpose of authenticating Customer End Users as valid
          and allowing access to the Concentric Network via Concentric
          RemoteLink. Customer is solely responsible for ensuring that the
          RADIUS Server operates and conforms to the specifications outlined in
          Exhibit D.

          5.2  Customer understands and agrees that if the RADIUS Server is not
          operational or accessible by the Concentric Network, or does not
          operate and conform to the specifications outlined in Exhibit D, that
          access to the Concentric RemoteLink service by Customer End Users may
          be severely impaired and/or cease entirely.

          5.3  Customer, at its sole discretion, may add or delete Customer End
          Users to or from the RADIUS Server. Customer, and not Concentric,
          controls who can be authenticated to have access to the Concentric
          RemoteLink/TM/ service. Customer, and not Concentric, is solely
          responsible for maintaining adequate network security practices,
          including establishment of appropriate firewalls, managing assignment
          of Customer End Users and the frequency of changes in login ID's and
          passwords.

          5.4  Customer is solely responsible for the operation of its home
          gateway and its internal corporate network including all routers,
          servers, applications and leased lines which interconnect with the
          Concentric RemoteLink/TM/ service.

          5.5  In the event that Customer selects and pays for Concentric to
          provide First Tier End User Support, Customer may provide Concentric
                                                        ---
          with a RADIUS test account ID/password if Customer desires Concentric
          help desk personnel to assist in the verification of the operation of
          Customer's RADIUS server.

          5.6  Customer is solely responsible for ensuring that: (a) Customer
          End Users have the necessary client software to access the Concentric
          RemoteLink service (e.g. stack and dialer software); and (b)
          Customer's designated in-house support personnel and network system
          administrators have the necessary client software to access
          ConcentricView, and /(COPYRIGHT)/ End Users are given valid ID's and
          passwords for access into the Customer's network. Concentric will hand
          off any first tier support calls to Customer's help desk, which appear
          to be related to invalid ID's or password s.

          5.7  In the event that Customer End Users use IP and PPP stack and
          dialer software other than the standard Windows '95 provided stack and
          dialer, and if Concentric is to 

                                       24
<PAGE>
 
          provide First Tier support of Customer End Users, then Customer is
          required to provide a copy of each stack and dialer to be supported to
          Concentric Customer Support.

          5.8  Customer is solely responsible for ensuring that End Users are
          given valid ID's and passwords for access into the Customer's network.
          If Concentric is performing First Tier support, Concentric will
          escalate any support calls which appear to be related to invalid ID's
          or passwords, to the Customer's help desk for resolution.
          
6.0       FEES AND BILLING

          6.1  Customer will pay Concentric all Fees for One Time Fees and
          Monthly Recurring Items selected by Customer in Exhibit C in
          accordance with the price schedule in Exhibit A.

          6.2  All Fees shall be paid at Concentric's option: (a) at
          Concentric's address as indicated in this Agreement or at such other
          address as Concentric may from time to time indicate by proper notice
          hereunder; or (b) by wire transfer to a bank and account number
          designated by Concentric. All invoices are due and payable within
          thirty (30) days of Concentric's date of invoice. Interest shall be
          payable at the rate of one percent (1%) per month or at the maximum
          rate permitted by law, whichever is less, on all overdue and unpaid
          invoices until paid in full.

          6.3  All Fees are in U.S. Dollars and are exclusive of any applicable
          taxes. Customer shall pay, indemnify and hold Concentric harmless from
          all sales, use, value added or other taxes of any nature, other than
          taxes on Concentric's net income, including penalties and interest,
          and all government permit or license fees assessed upon or with
          respect to any Fees (except to the extent Customer provides Concentric
          with a valid tax exemption certificate). If any applicable law
          requires Customer to withhold amounts from any payments to Concentric
          hereunder: (a) Customer shall effect such withholding, remit such
          amounts to the appropriate taxing authorities and promptly furnish
          Concentric with tax receipts evidencing the payments of such amounts;
          and (b) the sum payable by Customer upon which the deduction or
          withholding is based shall be increased to the extent necessary to
          ensure that, after such deduction or withholding, Concentric receives
          and retains, free from liability for such deduction or withholding, a
          net amount equal to the amount Concentric would have received and
          retained in the absence of such required deduction or withholding.

          6.4  The "Service Order Date" refers to the date Concentric receives
          and processes Customer's completed order, which results in activity by
          Concentric such as consultation, training and telco circuit ordering.
          The Service's Actual Startup date is three (3) business days after the
          day in which the telco circuit between Customer's site and the
          Concentric point-of-presence (POP) used for the Service is turned up
          (completed and activated by the 

                                       25
<PAGE>
 
          telco) and Customer is notified of such availability by Concentric.
          The "Anniversary Date" shall be the first day of the month following
          the Service's Actual Startup Date. Billing for the interim period
          between the Service's Actual Startup Date and the Anniversary Date
          shall be the daily pro-rata amount times the number of days between
          these two events plus the service's Actual Startup Date and shall be
          based on the estimated costs provided to Customer before the Service's
          order. This Interim Billing Period amount will be calculated and
          included on a subsequent Customer invoice. The first invoice will be
          generated shortly after the Service Order Date and is payable by
          Customer prior to the Actual Startup date of the Service. It will
          include: (i) estimated initial telco circuit installation fee; (ii)
          Concentric Service setup fee; (iii) initial month's Concentric Service
          fee (including any options selected by Customer on the Order Form);
          (iv) initial month's estimated telco circuit lease; (v) any equipment
          and/or software costs (if applicable). Subsequent monthly invoices
          will be for the specified month of Service and are payable upon the
          invoice due date. They will include subsequent month's Concentric
          Service fees and estimated or actual telco circuit lease. Any prorated
          fees incurred as part of the Interim Billing Period will be invoiced
          to and payable by Customer. Based on the actual telco circuit
          installation and monthly lease fees billed to Concentric by the telco,
          Concentric will pass-through any additional telco fees to Customer in
          the invoice following receipt of such telco's invoice. Concentric
          reserves the right to change the billing intervals upon written notice
          to Customer.

          6.5  Late Payments.  Invoices not paid by their due date shall be
          subject to a 1.5% per month interest fee, or the maximum extent
          allowed by applicable laws, whichever is less, on all past-due
          balances. In the event Concentric incurs additional fees as a result
          of any collection activity, such as collection agencies or legal fees,
          Customer shall reimburse Concentric for all such fees.

          6.6  Any upgrades of an existing Dedicated Access Service at a sub-
          rate of T1 to T1 or other higher T1 sub-rate Service shall incur the
          additional monthly Service fees seven (7) days after the upgrade
          Service Order Date, but this upgrade shall not incur any Concentric
          Service setup fees and the Anniversary Date shall become the first day
          of the month following the upgrade's Actual Startup Date as defined
          above with the new Interim Billing Period being calculated on a pro-
          rata basis and added to the next invoice. Upgrades shall cause this
          Agreement to automatically renew for a one (1) year term from the new
          Anniversary Date.

          6.7  All fees are in U.S. Dollars and are exclusive of any applicable
          taxes. Customer shall pay, indemnify and hold Concentric harmless from
          all sales, use, value added or other taxes of any nature, other than
          taxes on Concentric's net income, including penalties and interest,
          and all government permit or license fees assessed upon or with
          respect to any fees (except to the extent Customer provides Concentric
          with a valid tax exemption certificate). If any applicable law
          requires Customer to withhold amounts from any payments to Concentric
          hereunder: (a) Customer shall effect such withholding, remit such

                                       26
<PAGE>
 
          amounts to the appropriate taxing authorities and promptly furnish
          Concentric with tax receipts evidencing the payments of such amounts;
          and (b) the sum payable by Customer upon which the deduction or
          withholding is based shall be increased to the extent necessary to
          ensure that, after such deduction or withholding, Concentric receives
          and retains, free from liability for such deduction or withholding, a
          net amount equal to the amount Concentric would have received and
          retained in the absence of such required deduction or withholding.


7.0       REPRESENTATIONS AND WARRANTIES.

          7.1  Each party represents and warrants that it has the right and
          authority to enter into this Agreement, and that by entering into this
          Agreement, it will not violate, conflict with or result in a material
          default under any other contract, agreement, indenture, decree,
          judgment, undertaking, conveyance, lien or encumbrance to which it is
          a party or by which it or any of its property is or may become subject
          or bound. Each party shall not grant any rights under any future
          agreement, nor will it permit or suffer any lien, obligation or
          encumbrances that will conflict with the full enjoyment of either
          party of its rights under this Agreement.

          7.2  Customer represents and warrants that it will, at its own expense
          comply with all laws, regulations and other legal requirements that
          apply to this Agreement, including copyright and communications
          decency laws; advise Concentric of any legislation, rule, regulation
          or other law which is in effect or which may come into effect after
          the Effective Date and which affects the Customer's internal corporate
          network, local area network(s) or intranet, or the use of the
          Concentric RemoteLink/TM/ service in conjunction therewith, or 
          which has a material effect on any provision of this Agreement.
          Customer will provide Concentric with the assurances and official
          documents that Concentric periodically may request to verify
          Customer's compliance with this Section.

          7.3  Customer represents and warrants that no consent, approval or
          authorization of or designation, declaration or filing with any
          governmental authority is required in connection with the valid
          execution, delivery and performance of this Agreement.

          7.4  THE WARRANTY SET FORTH IN SECTION 7.1 IS THE SOLE AND EXCLUSIVE
          WARRANTY MADE BY CONCENTRIC. CONCENTRIC MAKES NO OTHER WARRANTY OF ANY
          KIND, EXPRESS OR IMPLIED, WITH RESPECT TO THE CONCENTRIC NETWORK,
          CONCENTRIC REMOTELINK, CONCENTRICVIEW AND THE CITYFIND SOFTWARE OR ANY
          RELATED NETWORK OR INTERNET SERVICES OR SOFTWARE. CONCENTRIC EXPRESSLY
          DISCLAIMS ANY: (a) WARRANTY OF DESIGN, MERCHANTABILITY,
          NONINFRINGEMENT OR FITNESS FOR A PARTICULAR PURPOSE, EVEN IF
          CONCENTRIC HAS BEEN INFORMED OF SUCH PURPOSE; 

                                       27
<PAGE>
 
          OR (b) WARRANTY THAT THE CONCENTRIC NETWORK, CONCENTRIC REMOTELINK,
          CONCENTRICVIEW, AND THE CITYFIND SOFTWARE OR ANY RELATED NETWORK OR
          INTERNET SERVICES OR SOFTWARE WILL BE ERROR-FREE, SECURE OR WITHOUT
          INTERRUPTION AND ALL LIABILITY ON ACCOUNT THEREOF.

8.0       LIMITATION OF LIABILITY.

          Except for a breach of Section 3.4, 9 or obligations arising under
          11.5, in no event shall a party shall be liable for special,
          incidental, consequential or punitive damages of any nature, for any
          reason, including without limitation any termination of this
          Agreement, whether such liability is asserted on the basis of
          contract, tort (including negligence or strict liability) or
          otherwise, even if a party has been warned of the possibility of such
          damages, and notwithstanding any failure of essential purpose of any
          limited remedy. NOTWITHSTANDING ANYTHING IN THIS AGREEMENT TO THE
          CONTRARY, CONCENTRIC'S ENTIRE LIABILITY TO CUSTOMER CONCERNING
          PERFORMANCE OR NONPERFORMANCE BY CONCENTRIC OR IN ANY WAY RELATED TO
          THE SUBJECT MATTER OF THIS AGREEMENT, AND REGARDLESS OF WHETHER A
          CLAIM IS BASED IN CONTRACT, NEGLIGENCE OR IN TORT, SHALL NOT EXCEED
          THE AMOUNT RECEIVED BY CONCENTRIC FROM CUSTOMER DURING THE PREVIOUS
          TWELVE (12) MONTHS.

9.0       CONFIDENTIAL INFORMATION

          Each party agrees to maintain all Confidential Information in
          confidence to the same extent that it protects its own similar
          Confidential Information and to use such Confidential Information only
          as permitted under this Agreement. For purposes of this Agreement
          "Confidential Information" shall mean information including, without
          limitation, computer programs, code, algorithms, names and expertise
          of employees and consultants, know-how, formulas, processes, ideas,
          inventions (whether patentable or not), schematics and other
          technical, business, financial and product development plans,
          forecasts, strategies and information marked "Confidential", or if
          disclosed verbally, is identified as confidential at the time of
          disclosure and reduced to a confidential writing within thirty (30)
          days after such disclosure. Each party agrees to take all reasonable
          precautions to prevent any unauthorized disclosure or use of
          Confidential Information including, without limitations disclosing
          Confidential Information only to its employees: (a) with a need to
          know to further permitted uses of such information; (b) who are
          parties to appropriate agreements sufficient to comply with this
          Section 9; and (c) who are informed of the nondisclosure/ non-use
          obligations imposed by this Section 9; and both parties shall take
          appropriate steps to implement and enforce such non-disclosure/non-use
          obligations. The foregoing restrictions on disclosure and use shall
          survive for three (3) years following termination of this Agreement
          but shall not apply with respect to any 

                                       28
<PAGE>
 
          Confidential Information which: (i) was or becomes publicly known
          through no fault of the receiving party; (ii) was rightfully known or
          becomes rightfully known to the receiving party without confidential
          or proprietary restriction from a source other than the disclosing
          party; (iii) is independently developed by the receiving party without
          the participation of individuals who have had access to the
          Confidential Information; (iv) is approved by the disclosing party for
          disclosure without restriction in a written document which is signed
          by a duly authorized officer of such disclosing party; and (v) the
          receiving party is legally compelled to disclose; provided, however,
          that prior to any such compelled disclosure, the receiving party will:
          (d) assert the privileged and confidential nature of the Confidential
          Information against the third party seeking disclosure; and (e)
          cooperate fully with the disclosing party in protecting against any
          such disclosure and/or obtaining a protective order narrowing the
          scope of such disclosure and/or use of the Confidential Information.
          In the event that such protection against disclosure is not obtained,
          the receiving party will be entitled to disclose the Confidential
          Information, but only as, and to the extent, necessary to legally
          comply with such compelled disclosure. Each of the parties hereto
          agrees not to disclose to any third party the terms of this Agreement
          without the prior written consent of the other party hereto, except to
          advisors, investors and others on a need-to-know basis under
          circumstances that reasonably ensure the confidentiality thereof, or
          to the extent required by law.

10.0      TERM AND TERMINATION

          10.1 The term of this Agreement shall commence on the Effective Date
          and continue until the term elected by Customer as set forth in
          Exhibit C. At the expiration of this initial term, this Agreement
          shall automatically renew for a term of one (1) year subject to
          Customer's acceptance of Concentric's then current Fees, unless notice
          of non-renewal is sent by either party no less than ninety (90) days
          before expiration of the term.

          10.2 Concentric may terminate this Agreement upon written notice: (a)
          for any material breach of this Agreement, which Customer fails to
          cure within thirty (30) days following written notice by Concentric of
          such breach; or (b) upon Customer's insolvency or liquidation as a
          result of which Customer ceases to do business for a continuous period
          of at least three (3) months. Customer may terminate this Agreement
          upon written notice: (a) for any material breach of this Agreement
          which Concentric fails to cure within thirty (30) days following
          written notice by Customer of such breach; or (b) upon Concentric's
          insolvency or liquidation as a result of which Concentric ceases to do
          business for a continuous period of at least three (3) months.

          10.3 Notwithstanding the expiration or termination of this Agreement,
          or anything to the contrary set forth herein, all TCP/IP addresses
          that are part of the Concentric Network remain the sole and exclusive
          property of Concentric.

11.0      OTHER PROVISIONS

                                       29
<PAGE>
 
          11.1 NON-ASSIGNMENT.  This Agreement shall be binding upon, and inure
          to the benefit of, the parties hereto and their respective successors
          and assigns. Notwithstanding the above, this Agreement may not be
          assigned in whole or in part by a party, without the written consent
          of the other party, which shall not be unreasonably withheld. Any
          assignment in violation of this paragraph shall be null and void.

          11.2 INDEPENDENT CONTRACTORS.  The parties shall have the status of
          independent contractors, and nothing in this Agreement shall be deemed
          to place the parties in the relationship of employer-employee,
          principal-agent, or partners or in a joint venture.

          11.3 NON-WAIVER.  Failure of either party to enforce any of its rights
          hereunder shall not be deemed to constitute a waiver of its future
          enforcement of such rights or any other rights.

          11.4 SEVERABILITY.  If any provision of this Agreement is held to be
          invalid, illegal, or unenforceable under present or future laws, such
          item shall be struck from the Agreement; however, such invalidity or
          enforceability shall not affect the remaining provisions or conditions
          of this Agreement. The parties shall remain legally bound by the
          remaining terms of this Agreement, and shall strive to reform the
          Agreement in a manner consistent with the original intent of the
          parties.

          11.5 CONTENT AND BREACH OF 3RD PARTY AGREEMENT INDEMNITY. Customer
          agrees to indemnify, hold harmless and upon request, defend
          Concentric, from and against any and all claims, liability, losses,
          damages, expenses and costs (including attorneys' fees) arising out of
          or in connection with: (a) information or content provided, accessed
          or made available by Customer on the Concentric Network; and; (b) any
          breach of any agreement for software, hardware or other products from
          third parties provided by Concentric hereunder.

          11.6 FORCE MAJEURE. Either party shall be excused from any delay or
          failure in performance hereunder caused by reason of any occurrence or
          contingency beyond its reasonable control, including but not limited
          to, acts of God, earthquake, labor disputes and strikes, riots, war or
          other unanticipated occurrences or problems, and governmental
          requirements. The obligations and rights of the party so excused shall
          be extended on a day-to-day basis for the period of time equal to that
          of the underlying cause of the delay.

          11.7 GOVERNING LAW.  This Agreement shall be deemed to have been made
          in the State of California, and the provisions and conditions of this
          Agreement shall be governed by and interpreted in accordance with the
          substantive laws of the State of California, without regard to
          conflict of laws provisions.

                                       30
<PAGE>
 
          11.8 ARBITRATION. Any dispute or claim arising out of or in connection
          with this Agreement or the performance, breach or termination thereof,
          shall be finally settled by binding arbitration in San Jose,
          California under the Rules of Arbitration of the American Arbitration
          Association by an arbitrator appointed in accordance with those rules.
          Judgment on the award rendered by the arbitrators may be entered in
          any court having jurisdiction thereof. Notwithstanding the foregoing,
          either party may apply to any court of competent jurisdiction for
          equitable relief without breach of this arbitration provision.

          11.9 INTEGRATION.  This Agreement expresses the complete and final
          understanding of the parties with respect to the subject matter
          hereof, and supersedes all prior communications between the parties,
          whether written or oral with respect to the subject matter hereof. No
          modification of this Agreement shall be binding upon the parties
          hereto, unless evidenced by a writing duly signed by authorized
          representatives of the respective parties hereto.

          11.10  NOTICES.  Any required notices hereunder shall be given in
          writing by certified mail or overnight express delivery service (such
          as DHL) at the address of each party below, or to such other address
          as either party may from time to time substitute by written notice.
          Notice shall be deemed served when delivered or, if delivery is not
          accomplished by reason or some fault of the addressee, when tendered.



          If to Concentric:                     If to Customer:

          RemoteLink Programs Manager
          Concentric Network Corporation
          10590 N. Tantau Ave.
          Cupertino, CA 95014
          408 342 2800

          AGREED AND ACCEPTED:


Concentric Network Corporation ("Concentric")                       ("Customer")
                                                -------------------

By:                                             By:
    -----------------------------                   ----------------------------
      (Authorized Signature)                            (Authorized Signature)

Name:                                           Name:
     ----------------------------                     --------------------------

                                       31
<PAGE>
 
Title:                                          Title:
      ---------------------------                      -------------------------

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

                                       32
<PAGE>
 
<TABLE> 
<CAPTION> 


                              IMPLEMENTATION PLAN
<C>             <S> 

__________      ORDER DAF

__________      ORDER RADIUS SERVER & SOFTWARE

__________      IDENTIFY IP ADDRESS RANGE

__________      PROVIDE CITYFIND SOFTWARE

__________      DELIVER ONE DAY FIRST TIER TRAINING SESSION FOR CUSTOMER (IF CUSTOMER PERFORMING FIRST TIER SUPPORT

__________      CONFIGURE CONCENTRIC ROUTER INTERFACE

__________      CONFIGURE TUNNEL MANAGEMENT SERVER WITH CUSTOMER INFORMATION

__________      DELIVER END USER DOCUMENTATION

__________      SET UP CUSTOMER ACCESS TO FRONTLINE SUPPORT TOOL (IF CUSTOMER TO PERFORM FIRST TIER SUPPORT)

__________      INSTALL CONCENTRICVIEW

__________      TURN UP SERVICE, TEST CONNECTIONS

</TABLE> 

                                       33
<PAGE>
 
                              CUSTOMER SELECTIONS


THE CONTRACT TERM SELECTED IS:__________.

THE SUPPORT OPTION SELECTED IS:

SECOND TIER SUPPORT ONLY:         ________________

FIRST TIER SUPPORT, 1 MINUTE ASA: ________________

FIRST TIER SUPPORT, 3 MINUTE ASA: ________________

FIRST TIER SUPPORT, __________ SHIFT SEATS, TO BE STAFFED DURING THE HOURS OF:

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

DAF CONNECTION TYPE DESIRED:    _________________________

DAF ONE TIME CHARGES:           _________________________

DAF MONTHLY CHARGES:            _________________________
 
DAF INSTALLATION CHARGES:       $3,000
 
ONE TIME OPTIONS DESIRED:
 
NT SERVER:        _______       RADIUS SOFTWARE:  ______
 
ROUTER:           _______       CSU:              ______

ON SITE INSTALL SUPPORT &
NETWORK MANAGEMENT TRAINING:  _________________________

END USER TRAINING COURSE:     _________________________

HELP DESK TRAINING COURSE:    _________________________

                                       34
<PAGE>
 
INITIALS, CONCENTRIC:_________________          CUSTOMER:____________________

                                       35
<PAGE>
 
                        SPECIFICATIONS FOR RADIUS SERVER

RADIUS SERVER SOFTWARE, IF PROVIDED BY THE CUSTOMER, SHALL CONFORM TO THE
CURRENT IETF SPECIFICATION, RFC 2058.

                                       36
<PAGE>
 
                                   EXHIBIT C
                            CNC TRADEMARK GUIDELINES


                        To Be Determined within 15 days

                                       37