<PAGE>
 
                                                                 EXHIBIT 10.47

                               RESELLER AGREEMENT

THIS RESELLER AGREEMENT (the "Agreement") is entered into as 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, Inc., a Delaware corporation with offices at One
Williams Center, 17/th/ 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,
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business, or institution that has contracted with WCG to purchase Services,
either as originally sold by CNC to WCG hereunder and resold to such Customer,
or as sold by CNC to WCG hereunder and resold to such Customer as part of a
value-added package offered by WCG.

"Dispute Resolution Procedures" shall mean the dispute resolution procedures set
 -----------------------------                                                  
forth in Section 33 of this Agreement.

"Effective Date" shall be the Closing Date described in that certain Common
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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 resale
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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 or commercially
unreasonable for CNC to offer under the WCG name in which case they shall be
made available to WCG on an agency basis.  "Services" shall include, but not be
limited to CNC Dedicated Access Facilities, Internet Dial Access, and
ConcentricHost Shared Web Services.  Subject to the foregoing, updates to the
current Exhibit A (including descriptions of the Services and the terms,
        ---------                                                       
conditions and service level agreements relating thereto as required under
Section 2) shall be made to this document as they become available .  CNC will
use commercially reasonable efforts to provide WCG the ability to be a reseller
via CNC for Telecom Italia International network services that are being
deployed as part of the CNC/Telecom Italia relationship.
<PAGE>
 
"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.  Current Subsidiaries are referenced
in Exhibit D.

2.  Non-Exclusive CNC Reseller.
    -------------------------- 

a)  Subject to the terms contained herein, CNC hereby grants to WCG during the
    term of this Agreement the non-exclusive, non-transferable right to
    purchase Services from CNC, with such purchases being in the name of WCG
    or any Subsidiaries (as amended (a current list of which shall be provided
    on a quarterly basis to CNC), and to resell such Services to Customers
    under the name of WCG or any of said Subsidiaries, including the right to
    grant non-exclusive, non-transferable sublicenses to Customers to use the
    software portions of the Services under the same software licensing terms
    that CNC utilizes, a copy of which as it pertains to CNC as of the
    Effective Date set forth in Exhibit Bor under substantially similar
    software licensing terms. Except as may be expressly set forth in writing
    by an authorized officer of CNC, WCG shall not have the authority to make
    any commitments whatsoever on behalf of CNC. WCG shall cooperate with CNC
    to avoid, and respond to, issues that arise relating to channel conflict.

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, and that it has the right to grant the reseller and
    sublicensing rights stated in the preceding paragraph and that such grant
    of reseller and sublicensing rights does not conflict with any prior
    license or other agreement entered into by CNC, and CNC agrees that it
    shall not enter into any license or other agreement in the future which
    conflicts with this Agreement.

c)  The respective terms and conditions and service level agreements for each
    Service purchased from CNC by WCG hereunder shall be attached to the
    portion of Exhibit A in which such Service is described as and when they
               ---------
    are mutually agreed upon by the Parties.

d)  WCG shall be responsible for establishing its own Customer pricing, terms
    and conditions of service, and service level agreements (collectively, the
    "Customer Terms"). In the event that Customer Terms are in conflict with
    the terms and conditions and service level agreements that CNC has with
    WCG, WCG acknowledges that any such conflicting Customer Terms will
    neither create additional obligations of CNC under this Agreement, lessen
    any obligations of WCG to CNC under this Agreement, nor otherwise affect
    the terms, conditions or service level agreements between CNC and WCG. WCG
    shall indemnify and hold CNC harmless from any claim, loss, damage or
    expense arising out of WCG's use of Customer Terms that are in conflict
    with the terms and conditions and service level agreements that CNC has
    with WCG.
<PAGE>
 
e)  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 and review the list of Subsidiaries of WCG. WCG will
    notify CNC of the current or developing Services from CNC that WCG desires
    to resell under the terms of this Agreement. For the designated Services
    that are currently available for resale, the Parties will on an expedited
    basis commence the development and implementation of the terms,
    conditions, service level agreements and pricing relating thereto (as
    provided in Sections 2(c) above and 4(b) below) so that WCG can begin
    representing CNC as a reseller for those Services. For the designated
    Services that are in the process of being developed, the Parties will
    develop and implement the terms, conditions, service level agreements and
    pricing relating thereto as soon as the development of the subject
    Services allows, so that WCG can begin representing CNC as a reseller for
    those Services immediately upon their availability to the public and
    without regard to the timing of the availability of those Services to
    other resellers, 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 to WCG for resale 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 with the requirements of this paragraph, then the
    Parties agree to resolve such disputes in accordance with the Dispute
    Resolution Procedures.

f)  It is WCG's desire to utilize WCG assets (e.g., circuits and computers)
    wherever and whenever technically and operationally feasible in support of
    CNC Services to be resold hereunder. WCG shall have the option of
    provisioning any part or all components required for product delivery,
    revenue collection (customer billing) and customer service, where
    technically and operationally feasible. Also, to the extent technically
    and operationally feasible with CNC's current support systems, CNC shall
    grant WCG access to the applications and control systems necessary for WCG
    to configure, maintain and support WCG's Customers. If necessary to enable
    any of the foregoing, and if technically and operationally feasible, and
    commercially feasible in light of CNC's then current engineering
    resources, CNC shall develop the necessary systems or make changes to CNC
    Services, and WCG shall reimburse CNC therefor on a fully-allocated basis.
    The price paid by WCG to CNC for Services will be dependent on which
    components of each of the various Services WCG provides. CNC and WCG shall
    mutually agree upon development objectives, schedules and costs before
    initiating any WCG-funded development projects.

g)  WCG shall provide CNC with WCG's requirements for dial-up services. CNC
    shall use commercially reasonable efforts to assist WCG on an expedited
    basis so as to enable WCG to resell the CNC Dial Access Service within 30
    days of the Effective Date.
<PAGE>
 
3.        Independent Contractors.  The relationship of CNC and WCG established
          -----------------------                                              
by this Agreement is that of independent contractors, and 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 or be construed to create or
imply a joint venture, partnership, principal-agent, or employment relationship.
WCG shall not have the authority to make any commitments whatsoever on behalf of
CNC.  All financial and other obligations associated with WCG's business as a
reseller are the sole responsibility of WCG.

4.        Pricing to WCG.
          -------------- 

a)  Most Favored Nation Status.  Discounts, 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 prices, terms, and conditions offered to
    WCG under this Agreement are no less favorable than the prices, terms, and
    conditions, taken as a whole and not individually, provided to any other
    CNC reseller. CNC will provide a nationally recognized independent third
    party auditor retained by WCG access upon thirty (15) days prior notice,
    at WCG's expense, to other active reseller 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 reseller
    has more favorable prices, terms and conditions, then CNC will give WCG
    the opportunity to substitute all of the prices, terms and conditions that
    apply to such other reseller for the prices, 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)  Cost Plus Status.  Subject to the terms of Section 4(a), CNC is offering
    ----------------                                                        
    Services to WCG under this Agreement on a Cost Plus basis. The principal
    of Cost Plus is that all Direct Costs of providing service including,
    without limitation, capital, labor, telecommunications services, etc. will
    be marked-up by a factor that will cover CNC's target Operating Expenses
    (Engineering, Sustaining Sales & Marketing, product management and G&A) as
    well as a target Profit Before Tax. For illustrative purposes only, a
    fictional product (code name IMPACT) has been used for Exhibit C1. The
                                                           ----------
    Direct Costs, Operating Expenses, and Profit Before Tax targets will be
    jointly developed and agreed upon by the Parties for each product to be
    resold in the manner described in Exhibit C1, and the pricing ultimately
                                      ----------
    developed for each Service will be set forth in the attachment to Exhibit
                                                                      -------
    A that relates to the Service being priced. In developing these cost
    -
    estimates and targets, the following principles will apply:

    i.    Direct costs of capital include lease (Depreciation & Interest),
          installation, and maintenance expenses.
    ii.   Labor costs are fully burdened by benefits/taxes and departmental
          overhead.
    iii.  Telecommunications services expense includes non-recurring and
          recurring monthly expenses and all applicable taxes.
    iv.   An appropriate "capacity utilization" factor will be applied to
          Capital and Telecommunications expenses to account for the fact that
          capacity must be installed in advance of demand and that capacity
          cannot be utilized at 100% efficiency levels.
    v.    Engineering and G&A Operating Expense will be targeted at levels
          consistent with CNC's next twelve month budget as a percent of
          revenue.
<PAGE>
 
    vi.   Sales & Marketing expense will include the direct costs of any
          dedicated staff assigned to support WCG from a sales, marketing,
          and/or systems engineering level plus X% to cover allocated
          sustaining Sales & Marketing expense. The parties will jointly agree
          on "X", but it is estimated to be in the 2-4% of revenue range.

    vii.  Target Profit Before Tax will be set at a level to reflect the
          steady-state Profit Target expected of CNC by analysts and
          investors. The parties will jointly agree on this target, but it is
          estimated to be in the 10-15% of revenue range.

c)  Adjustments.  The discounts, 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. Also, the costing metrics and the related
    terms and conditions of this Agreement described in Section 4(b) will be
    reviewed annually and updated as appropriate for the subsequent twelve
    month period of this Agreement. 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
    sentences, then the Parties agree to resolve the dispute in accordance
    with the Dispute Resolution Procedures.

5.        Invoicing and Payment.  Unless otherwise provided in the terms and
          ---------------------                                             
conditions set forth in Exhibit A with respect to a particular Service, CNC will
invoice WCG at the beginning of each month for all Services rendered (or
products delivered, as the case may be) during the preceding month.  Terms of
payment for Services shall be net 30 days from date of the applicable invoice.
WCG is responsible for billing and collection from its Customers.  Payments to
CNC by WCG will not be conditioned upon or delayed by WCG's attempts to collect
from its Customers nor will CNC be liable for any service credits that WCG may
elect to provide to its Customers.

6.        Taxes.  Except as otherwise provided herein, CNC shall bear all taxes,
          -----                                                                 
import and export duties, and other governmental fees of whatever nature imposed
on transactions hereunder, except federal, state or local sales and use taxes
applicable to the sale of Services, which sales and use taxes shall be added to
the prices as applicable and stated as separate items on each invoice applicable
to each order for Services, unless WCG provides CNC with evidence of a resale
certificate acceptable to the taxing authority in question.

7.        Quotas.  Subsequent to a reasonable amount of time following initial
          ------                                                              
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 purchase 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.
<PAGE>
 
8.        Training and Sales Support.  CNC will provide, at its expense, a
          --------------------------                                      
designated point-of-contact for sales and/or technical support questions that
will be shared with other CNC channel organizations.  Additional sales and/or
technical support will be provided to WCG at WCG's expense and subject to mutual
agreement.  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 reasonable 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.
CNC will provide either camera-ready copy or, at WCG's expense, quantities of
sales promotion literature and materials.

9.        Infringement Indemnity.  The following terms apply to any infringement
          ----------------------                                                
or claim alleging infringement by WCG or its Customers 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. CNC shall indemnify, defend and hold harmlessWCG, its owners or
Customers, 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.

In addition, if in such action or suit WCG or any of its Customers' use of the
Services or any component thereof is held to constitute an infringement and such
use is enjoined, CNC shall promptly at its expense, either (1) procure for WCG
and its Customers the right to continue using the Services or the affected
portion thereof, or (2) after consultation with WCG, replace or modify the
affected portion of the Services to make them substantially similar,
functionally equivalent, non-infringing Services.  If CNC is unable or
determines that it is commercially impractical to do either (1) or (2) within a
commercially reasonable time, CNC shall at its own expense take back the
infringing product or discontinue providing the infringing service, as the case
may be, and promptly refund the price paid for same by WCG as depreciated using
generally accepted accounting practices.

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.

10.       Non-exclusive Reseller 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 contract with others for the purchase of
products or services of the types which are the subject of this Agreement.
<PAGE>
 
11.       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.

12.       Orders and Provisioning.  WCG and CNC will jointly develop, at WCG's
          -----------------------                                             
expense, order entry and provisioning processes for each product to be resold
under the terms of this Agreement.  Such processes will be designed to minimize
the total cost of order processing and provisioning while minimizing cycle-time
and maximizing customer satisfaction.

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.       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
("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 right
to indicate to the public that it is an authorized reseller of CNC's Services
and to advertise such Services under the Trademarks according to CNC style
guides referenced in Exhibit D.  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.

15.       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 thirty (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.

16.       Reporting.  CNC shall provide WCG with monthly detail reports on the
          ---------                                                           
Services and 
<PAGE>
 
service elements that WCG has purchased from CNC and resold to WCG's Customers
in a form suitable to both Parties, written or electronic.

17. 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.

18. 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, or its Customers,
    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 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.

19. 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 20 (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 20 (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.

20. 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 
<PAGE>
 
    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 9 (Infringement Indemnity), Section 11 (Indemnification),
and Section 22 (Confidential Information)

21.       Transition Period.  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
Customers.

22.       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 
<PAGE>
 
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.

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  THE OTHER SHALL
IN ANY EVENT EXCEED THE AMOUNT RECEIVED BY CNC FROM WCG DURING THE PREVIOUS
TWELVE (12) MONTHS; PROVIDED, HOWEVER, THAT THE FOREGOING LIMITATION SHALL NOT
APPLY TO LIMIT LIABILITY AMOUNTS ARISING FROM SECTIONS 9 AND 11

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 gives the other Party prompt notice of such condition.

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

a.        require the Party experiencing the delay to continue performance as
soon as practicable after the delay has ended; or
<PAGE>
 
b.        terminate without penalty any affected order for Services or portion
thereof by giving written notice to the Party experiencing the delay.

Such other Party may select option (a) as to certain orders for Services or
parts thereof and option (b) as to other affected orders for Services or parts
thereof.  In the absence of notice of selection of any option with respect to a
particular affected order for Services, 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

b. 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 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 
<PAGE>
 
    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          WILLIAMS COMMUNICATIONS GROUP, INC.
 ("CNC")                                              ("WCG")


By: /s/ Henry R. Nothhaft               By: /s/ S. Miller Williams
   __________________________________      __________________________________

Printed Name: Henry R. Nothhaft         Printed Name: /s/ S. Miller Williams
            _________________________               _________________________

Title:  President & CEO                 Title:  Sr. Vice President
     ________________________________        ________________________________
<PAGE>
 
                                  EXHIBIT A
                                  ---------

                           DESCRIPTION OF SERVICES
                           -----------------------

Placeholder for attachments of each Service setting forth the terms, conditions,
           service level agreements and pricing relating thereto.


                                 WCG PRICING
                                 -----------
<TABLE>
<CAPTION>
 
PRODUCT                  CNC LIST   WCG PRICE
<S>                     <C>         <C>
Full T-1                    $2,095     $1,375
Full T-1 Usage based        $1,095     $  725
Flex 512K                   $1,895     $1,030
Flex 128K                   $  895     $  645
Frame 56K                   $  395     $  325
DAF Startup                 $3,000     $1,995
RemoteLink                  $2.55/Hr.  $ 1.79
Internet Dail Access        $19.95/Mo. $14.95
</TABLE>
Notes:

1. These prices will be in effect until the parties conduct cost studies and
   agree on cost-plus pricing for these services in accordance with paragraph
   4(b) of this Agreement. The parties agree to work in good faith to complete
   these analyses by August 30, 1997.

2. WCG is responsible for all sales, sales support, marketing, first tier
   customer support, and end-Customer billing
<PAGE>
 
                                  EXHIBIT B
                                  ---------

                         SOFTWARE SUBLICENSING TERMS
                         ---------------------------

Replace with the license agreement we use and are required to use.

 END USER LICENSE AGREEMENT FOR CITYFIND SOFTWARE

IMPORTANT NOTICE - READ CAREFULLY! This End User License Agreement for CityFind
Software ("EULA") is a legal agreement between you and Concentric Network
Corporation ("CONCENTRIC") for the CityFind software and any associated
documentation. By installing or using the CityFind software, you are agreeing to
be bound by the terms of this EULA. If you do not agree to the terms of this
EULA, do not install or use the CityFind software. Use of the CityFind Software
is contingent on your agreement to the following terms:

1. GRANT OF LICENSE AND LICENSE RESTRICTIONS.

CONCENTRIC grants to you a limited, non-exclusive, nontransferable, royalty-free
license to use one copy of the executable code of the CityFind software on a
single CPU if you have been authorized to use the CONCENTRIC RemoteLink(TM)
remote access service.  The CityFind software may only be used in conjunction
with the Concentric RemoteLink outsourced remote access service. The CityFind
software is protected by copyright laws and international copyright treaties, as
well as other intellectual property laws and treaties. You may not rent, lease,
sell, sublicense, assign, or otherwise transfer the CityFind software, including
any accompanying printed materials. You may not reverse engineer, decompile or
disassemble the CityFind software except to the extent that this restriction is
expressly prohibited by applicable law. CONCENTRIC and its suppliers shall
retain title and all ownership rights to the CityFind software.

2. CITYFIND SOFTWARE MAINTENANCE.

CONCENTRIC is not obligated to provide maintenance or updates to you for
the CityFind software. However, any maintenance or updates provided by
CONCENTRIC are licensed to you under the terms of this Agreement.

3. DISCLAIMER OF WARRANTY.

CityFind software is deemed accepted by you. The CITYFIND SOFTWARE is provided
"AS IS" WITHOUT WARRANTY OF ANY KIND. TO THE MAXIMUM EXTENT PERMITTED BY
APPLICABLE LAW, CONCENTRIC DISCLAIMS ALL WARRANTIES, INCLUDING WITHOUT
LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE, AND NONINFRINGEMENT. THE ENTIRE RISK ARISING OUT OF THE USE OR
PERFORMANCE OF THE CITYFIND SOFTWARE AND DOCUMENTATION REMAINS WITH YOU.

4. LIMITATION OF LIABILITY.

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, IN NO EVENT 
<PAGE>
 
SHALL CONCENTRIC OR ITS SUPPLIERS BE LIABLE FOR ANY CONSEQUENTIAL, INCIDENTAL,
DIRECT, INDIRECT, SPECIAL, PUNITIVE, OR OTHER DAMAGES WHATSOEVER (INCLUDING,
WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS
INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR OTHER PECUNIARY LOSS) ARISING
OUT OF THIS AGREEMENT OR THE USE OF OR INABILITY TO USE THE CITYFIND SOFTWARE,
EVEN IF CONCENTRIC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
BECAUSE SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR
CONSEQUENTIAL OR INCIDENTAL DAMAGES, THE ABOVE LIMITATION MAY NOT APPLY TO
YOU.

5. U.S. GOVERNMENT RESTRICTED RIGHTS AND EXPORT RESTRICTIONS.

The CityFind software is provided with RESTRICTED RIGHTS. Use, duplication, or
disclosure by the Government is subject to restrictions as set forth in
subparagraph (c)(1)(ii) of The Rights in Technical Data and Computer Software
clause of DFARS 252.227-7013 or subparagraphs (c)(i) and (2) of the Commercial
Computer Software-Restricted Rights at 48 CFR 52.227-19, as applicable.
Manufacturer is Concentric Network Corporation, 10590 N. Tantau Ave., Cupertino,
CA 95014. You agree that  you will not export or re-export the CityFind
software, directly or indirectly to: (i) any countries that are subject to
U.S.A. export restrictions (currently including, but not necessarily limited to,
Cuba, Iran, Iraq, Libya, North Korea, and Syria); or (iii) any end user who is
listed on the Table of Denial Orders. You further acknowledge that the CityFind
software may include technical data subject to export and re-export
restrictions imposed by U.S.A. law.

6. TERMINATION.

This EULA terminates when you are no longer authorized to use the Concentric
RemoteLink outsourced remote access service. Without prejudice to any other
rights, CONCENTRIC may terminate this EULA if you fail to comply with the terms
and conditions of this EULA. Upon termination of this EULA, you must destroy all
copies of the CityFind software.

7. GOVERNING LAW; ATTORNEYS FEES.

This Agreement shall be governed by the laws of the State of California and you
consent to jurisdiction by the state and federal courts in the State of
California. If either CONCENTRIC or you employs attorneys to enforce any rights
arising out of or relating to this Agreement, the prevailing party shall be
entitled to recover reasonable attorneys' fees.

8. ENTIRE AGREEMENT.

This Agreement constitutes the complete and exclusive agreement between
CONCENTRIC and you with respect to the subject matter hereof, and supersedes all
prior oral or written understandings, communications or agreements not
specifically incorporated herein.  This Agreement may not be modified except in
a writing duly signed by an authorized representative of CONCENTRIC.

Copyright 1996, 1997  Concentric Networks Corporation
http://home.concentric.net
<PAGE>
 
NETSCAPE NAVIGATOR END USER LICENSE AGREEMENT
REDISTRIBUTION NOT PERMITTED

This Agreement has 3 parts. Part I applies if you have not purchased a license
to the accompanying software (the "Software"). Part II applies if you have
purchased a license to the Software. Part III applies to all license grants.
If you initially acquired a copy of the Software without purchasing a license
and you wish to purchase a license, contact Netscape Communications
Corporation ("Netscape") on the Internet at http://www.netscape.com.

PART I -- TERMS APPLICABLE WHEN LICENSE FEES NOT (YET) PAID (LIMITED TO
EVALUATION, EDUCATIONAL AND NON-PROFIT USE) GRANT.

Netscape grants you a non-exclusive license to use the Software free of charge
if (a) you are a student, faculty member or staff member of an educational
institution (K-12, junior college, college or library), a staff member of a
religious organization, or an employee of an organization which meets
Netscape's criteria for a charitable non-profit organization; or (b) your use
of the Software is for the purpose of evaluating whether to purchase an
ongoing license to the Software. The evaluation period for use by or on behalf
of a commercial entity is limited to 90 days; evaluation use by others is not
subject to this 90 day limit. Government agencies (other than public
libraries) are not considered educational, religious, or charitable non-profit
organizations for purposes of this Agreement. If you are using the Software
free of charge, you are not entitled to hard-copy documentation, support or
telephone assistance. If you fit within the description above, you may use the
Software in the manner described in Part III below under "Scope of Grant."

DISCLAIMER OF WARRANTY.

Free of charge Software is provided on an "AS IS" basis, without warranty of
any kind, including without limitation the warranties of merchantability,
fitness for a particular purpose and non-infringement. The entire risk as to
the quality and performance of the Software is borne by you. Should the
Software prove defective, you and not Netscape assume the entire cost of any
service and repair. In addition, the security mechanisms implemented by
Netscape software have inherent limitations, and you must determine that the
Software sufficiently meets your requirements. This disclaimer of warranty
constitutes an essential part of the agreement. SOME JURISDICTIONS DO NOT
ALLOW EXCLUSIONS OF AN IMPLIED WARRANTY, SO THIS DISCLAIMER MAY NOT APPLY TO
YOU AND YOU MAY HAVE OTHER LEGAL RIGHTS THAT VARY BY JURISDICTION.

PART II -- TERMS APPLICABLE WHEN LICENSE FEES PAID

GRANT. Subject to payment of applicable license fees, Netscape grants to you a
non-exclusive license to use the 
<PAGE>
 
Software and accompanying documentation ("Documentation") in the manner
described in Part III below under "Scope of Grant."

LIMITED WARRANTY.

Netscape warrants that for a period of ninety (90) days from the date of
acquisition, the Software, if operated as directed, will substantially achieve
the functionality described in the Documentation. Netscape does not warrant,
however, that your use of the Software will be uninterrupted or that the
operation of the Software will be error-free or secure. In addition, the
security mechanisms implemented by Netscape software have inherent
limitations, and you must determine that the Software sufficiently meets your
requirements. Netscape also warrants that the media containing the Software,
if provided by Netscape, is free from defects in material and workmanship and
will so remain for ninety (90) days from the date you acquired the Software.
Netscape's sole liability for any breach of this warranty shall be, in
Netscape's sole discretion: (i) to replace your defective media; or (ii) to
advise you how to achieve substantially the same functionality with the
Software as described in the Documentation through a procedure different from
that set forth in the Documentation; or (iii) if the above remedies are
impracticable, to refund the license fee you paid for the Software. Repaired,
corrected, or replaced Software and Documentation shall be covered by this
limited warranty for the period remaining under the warranty that covered the
original Software, or if longer, for thirty (30) days after the date (a) of
shipment to you of the repaired or replaced Software, or (b) Netscape advised
you how to operate the Software so as to achieve the functionality described
in the Documentation. Only if you inform Netscape of your problem with the
Software during the applicable warranty period and provide evidence of the
date you purchased a license to the Software will Netscape be obligated to
honor this warranty. Netscape will use reasonable commercial efforts to
repair, replace, advise or, for individual consumers, refund pursuant to the
foregoing warranty within 30 days of being so notified.

THIS IS A LIMITED WARRANTY AND IT IS THE ONLY WARRANTY MADE BY NETSCAPE.
NETSCAPE MAKES NO OTHER EXPRESS WARRANTY AND NO WARRANTY OF NONINFRINGEMENT OF
THIRD PARTIES' RIGHTS. THE DURATION OF IMPLIED WARRANTIES, INCLUDING WITHOUT
LIMITATION, WARRANTIES OF MERCHANTABILITY AND OF FITNESS FOR A PARTICULAR
PURPOSE, IS LIMITED TO THE ABOVE LIMITED WARRANTY PERIOD; SOME JURISDICTIONS
DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED WARRANTY LASTS, SO LIMITATIONS
MAY NOT APPLY TO YOU. NO NETSCAPE DEALER, AGENT, OR EMPLOYEE IS AUTHORIZED TO
MAKE ANY MODIFICATIONS, EXTENSIONS, OR ADDITIONS TO THIS WARRANTY. If any
modifications are made to the Software by you during the warranty period; if
the media is subjected to accident, abuse, or improper use; or if you violate
the terms of this Agreement, then this warranty shall immediately be
terminated. 
<PAGE>
 
This warranty shall not apply if the Software is used on or in conjunction
with hardware or software other than the unmodified version of hardware and
software with which the software was designed to be used as described in the
Documentation. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY HAVE
OTHER LEGAL RIGHTS THAT VARY BY JURISDICTION.

PART III -- TERMS APPLICABLE TO ALL LICENSE GRANTS

SCOPE OF GRANT.

You may:
* use the Software on any single computer;
* use the Software on a network, provided that each person accessing the
  Software through the network must have a copy licensed to that person;
* use the Software on a second computer so long as only one copy is used at a
  time;
* copy the Software for archival purposes, provided any copy must contain all
  of the original Software's proprietary notices; or
* if you have purchased licenses for a 10 Pack or a 50 Pack, make up to 10 or
  50 copies, respectively, of the Software (but not the Documentation),
  provided any copy must contain all of the original Software's proprietary
  notices. The number of copies is the total number of copies that may be made
  for all platforms. Additional copies of Documentation may be purchased.

You may not:
* permit other individuals to use the Software except under the terms listed
  above;
* permit concurrent use of the Software;
* modify, translate, reverse engineer, decompile, disassemble (except to the
  extent applicable laws specifically prohibit such restriction), or create
  derivative works based on the Software;
* copy the Software other than as specified above;
* rent, lease, grant a security interest in, or otherwise transfer rights to
  the Software; or
* remove any proprietary notices or labels on the Software.

TITLE.

Title, ownership rights, and intellectual property rights in the Software
shall remain in Netscape and/or its suppliers. The Software is protected by
the copyright laws and treaties. Title and related rights in the content
accessed through the Software is the property of the applicable content owner
and may be protected by applicable law. This License gives you no rights to
such content.

TERMINATION.

The license will terminate automatically if you fail to comply with the
limitations described herein. On
<PAGE>
 
termination, you must destroy all copies of the Software and Documentation.

EXPORT CONTROLS.

None of the Software or underlying information or technology may be downloaded
or otherwise exported or reexported (i) into (or to a national or resident of)
Cuba, Iraq, Libya, Yugoslavia, North Korea, Iran, Syria or any other country
to which the U.S. has embargoed goods; or (ii) to anyone on the U.S. Treasury
Department's list of Specially Designated Nationals or the U.S. Commerce
Department's Table of Denial Orders. By downloading or using the Software, you
are agreeing to the foregoing and you are representing and warranting that you
are not located in, under the control of, or a national or resident of any
such country or on any such list.

In addition, if the licensed Software is identified as a not-for-export
product (for example, on the box, media or in the installation process), then
the following applies: EXCEPT FOR EXPORT TO CANADA FOR USE IN CANADA BY
CANADIAN CITIZENS, THE SOFTWARE AND ANY UNDERLYING TECHNOLOGY MAY NOT BE
EXPORTED OUTSIDE THE UNITED STATES OR TO ANY FOREIGN ENTITY OR "FOREIGN
PERSON" AS DEFINED BY U.S. GOVERNMENT REGULATIONS, INCLUDING WITHOUT
LIMITATION, ANYONE WHO IS NOT A CITIZEN, NATIONAL OR LAWFUL PERMANENT RESIDENT
OF THE UNITED STATES. BY DOWNLOADING OR USING THE SOFTWARE, YOU ARE AGREEING
TO THE FOREGOING AND YOU ARE WARRANTING THAT YOU ARE NOT A "FOREIGN PERSON" OR
UNDER THE CONTROL OF A FOREIGN PERSON.

LIMITATION OF LIABILITY. UNDER NO CIRCUMSTANCES AND UNDER NO LEGAL THEORY,
TORT, CONTRACT, OR OTHERWISE, SHALL NETSCAPE OR ITS SUPPLIERS OR RESELLERS BE
LIABLE TO YOU OR ANY OTHER PERSON FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES OF ANY CHARACTER INCLUDING, WITHOUT LIMITATION, DAMAGES
FOR LOSS OF GOODWILL, WORK STOPPAGE, COMPUTER FAILURE OR MALFUNCTION, OR ANY
AND ALL OTHER COMMERCIAL DAMAGES OR LOSSES. IN NO EVENT WILL NETSCAPE BE
LIABLE FOR ANY DAMAGES IN EXCESS OF THE AMOUNT NETSCAPE RECEIVED FROM YOU FOR
A LICENSE TO THE SOFTWARE, EVEN IF NETSCAPE SHALL HAVE BEEN INFORMED OF THE
POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. THIS
LIMITATION OF LIABILITY SHALL NOT APPLY TO LIABILITY FOR DEATH OR PERSONAL
INJURY TO THE EXTENT APPLICABLE LAW PROHIBITS SUCH LIMITATION. FURTHERMORE,
SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THIS LIMITATION AND EXCLUSION MAY NOT APPLY TO YOU.

HIGH RISK ACTIVITIES.

The Software is not fault-tolerant and is not designed, manufactured or
intended for use or resale as on-line control equipment in hazardous
environments requiring fail-safe performance, such as in the operation of
nuclear facilities, aircraft navigation or communication
<PAGE>
 
systems, air traffic control, direct life support machines, or weapons
systems, in which the failure of the Software could lead directly to death,
personal injury, or severe physical or environmental damage ("High Risk
Activities"). Netscape and its suppliers specifically disclaim any express or
implied warranty of fitness for High Risk Activities.

MISCELLANEOUS.

If the copy of the Software you received was accompanied by a printed or other
form of "hard-copy" End User License Agreement whose terms vary from this
Agreement, then the hard-copy End User License Agreement governs your use of
the Software. This Agreement represents the complete agreement concerning this
license and may amended only by a writing executed by both parties. THE
ACCEPTANCE OF ANY PURCHASE ORDER PLACED BY YOU IS EXPRESSLY MADE CONDITIONAL
ON YOUR ASSENT TO THE TERMS SET FORTH HEREIN, AND NOT THOSE IN YOUR PURCHASE
ORDER. If any provision of this Agreement is held to be unenforceable, such
provision shall be reformed only to the extent necessary to make it
enforceable. This Agreement shall be governed by California law (except for
conflict of law provisions). The application the United Nations Convention of
Contracts for the International Sale of Goods is expressly excluded.

U.S. GOVERNMENT RESTRICTED RIGHTS. Use, duplication or disclosure by the
Government is subject to restrictions set forth in subparagraphs (a) through
(d) of the Commercial Computer-Restricted Rights clause at FAR 52.227-19 when
applicable, or in subparagraph (c)(1)(ii) of the Rights in Technical Data and
Computer Software clause at DFARS 252.227-7013, or at 252.211-7015, or to
Netscape's standard commercial license, as applicable, and in similar clauses
in the NASA FAR Supplement. Contractor/manufacturer is Netscape Communications
Corporation, 501 East Middlefield Road, Mountain View, CA 94043.
<PAGE>
 
                                  EXHIBIT C
                                  ---------

WCG COST PLUS PRICING MODEL
----------------------------

                       FOR ILLUSTRATIVE PURPOSES ONLY
                       ------------------------------

 
 
PRODUCT:  IMPACT
----------------
 
 
LINE ITEM DESCRIPTIONS              PRICING  PERCENTAGES
----------------------              -------  -----------
WCG PRICE (CNC REVENUE)                $478          100%
 
 
Backbone (8:1 usage)                   $100           21%
 
Hardware (assumes 4% lease rate)       $100           21%
 
Network Management                     $ 50         10.5%
 
Customer Service                       $ 50         10.5%
 
Billing                                $ 25            5%
-------                                ----         ----
TOTAL CNC COGS                         $325           68%
 
 
GROSS MARGIN                           $153           32%
 
 
R & D                                  $ 33            7%
 
Sales & Marketing                      $ 19            4%
 
G & A                                  $ 29            6%
-----                                  ----         ----
OPERATING EXPENSES                     $ 81           17%

 
PBT                                    $ 72           15%
===                                    ====         ====

                       FOR ILLUSTRATIVE PURPOSES ONLY
                       ------------------------------
<PAGE>
 
                                  EXHIBIT D
                                  ---------

                          CNC TRADEMARK GUIDELINES
                          ------------------------

                               To be provided
                               --------------