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                                                                   EXHIBIT 10.21

                           SOFTWARE LICENSE AGREEMENT
                            (SOURCE AND OBJECT CODE)

This Software License Agreement, including the exhibits and attachments hereto
(the "AGREEMENT"), is effective as of the Effective Date set forth below,
between ISOCOR, a California corporation located at 3420 Ocean Park Blvd, Santa
Monica, CA 90405, ("ISOCOR"), and Netscape Communications Corporation, a
Delaware corporation located at 501 East Middlefield Road, Mountain View, CA
94043 and its wholly-owned subsidiaries (collectively "NETSCAPE"), under which
ISOCOR grants Netscape certain rights in the source code ("SOURCE CODE") and
object code ("OBJECT CODE") of the specified software developed or licensed by
ISOCOR (the "LICENSED PROGRAMS"), each as further described herein, for use in
Netscape's products (the "PRODUCTS") as defined below.

1.      DEFINITIONS

        1.1     "ACCEPTANCE" shall mean (a) Acceptance as defined in Exhibit A,
                Section 2; (b) shipment of a Product containing all or any
                portion of the Licensed Programs to any customer; or (c) the
                failure of Netscape to notify ISOCOR of the acceptance or
                rejection of the Acceptance Candidates within [***] after 
                receipt of the Acceptance Candidates.

        1.2     "ACCEPTANCE TEST" shall mean a series of test procedures
                mutually developed by Netscape and ISOCOR on or before November
                31, 1998 and designed to prove that the Acceptance Candidates
                reasonably perform according to the Specifications, which shall
                include, at a minimum, the test criteria set forth in Exhibit F
                attached hereto.

        1.3     "ACCEPTANCE CANDIDATES" shall mean the version of (a) the Source
                Code and Object Code of the ISOCOR Join Engine; and (b) the
                Source Code and Object Code of the Text Universal Connector,
                which are designated by ISOCOR as Acceptance Candidates and
                Netscape tests using the Acceptance Test for Acceptance pursuant
                to the terms and conditions of this Agreement.

        1.4     [***]

        1.5     "CONNECTOR(S)" shall be defined as connector software which
                enables foreign systems/directories to be accessed by the ISOCOR
                Join Engine and which shall contain, at a minimum, those
                features set forth in the Specifications. Connectors shall
                include the Exclusive Connectors (as defined below) and Standard
                Connectors (both as defined below), but shall not include the
                Text Universal Connector (as defined below).

        1.6     "CONTROL" means the direct or indirect beneficial ownership of
                fifty (50%) or more of the voting interests (representing the
                right to vote for the election of directors or other managing
                authority) in an entity as of the date that Netscape grants such
                entity a sublicense to the Licensed Programs.

        1.7     "DOCUMENTATION" means any available end user or reference
                documentation delivered to Netscape hereunder: (a) related to
                the use of the applicable form of the Licensed Programs and/or
                (b) described in Exhibit E.

        1.8     "EXCLUSIVE CONNECTOR(S)" shall mean the ISOCOR Connectors ([***]
                platform) listed in Exhibit C attached hereto.


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


             
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        1.9     "EXCLUSIVITY PERIOD" means the period of [***] from the Netscape
                Join Engine Release Date (Section 1.4(a) of Exhibit B).

        1.10    "GENERAL RELEASE" means the shipment date of the first non-beta
                or non-alpha delivery of a production version of a Licensed
                Program or Product to a customer in the ordinary course of
                business.

        1.11    "ISOCOR CONNECTOR(S)" shall be defined as ISOCOR's Connector
                software on [***] which shall contain, at a minimum, those
                features set forth in the Technology Specifications (as defined
                herein).

        1.12    "ISOCOR JOIN ENGINE" shall be defined as ISOCOR's meta-directory
                management software on [***] Platform which shall contain, at a
                minimum, those features set forth in the Specifications. The
                ISOCOR Join Engine shall also include a join engine that
                contains Netscape modifications to the wrapper, icons, help
                Section or about Section of the ISOCOR Join Engine but maintains
                its user interface.

        1.13    "ISOCOR MANAGEMENT CONSOLE" shall mean the ISOCOR's Management
                Center which operates on the [***] platform which contains a
                Join Administration graphic user interface for the Join Engine
                and Connectors which will support multiple simultaneous join
                administrators for manual join purposes, and which shall
                contain, at a minimum, those features set forth in the
                Technology Specifications.

        1.14    "ISOCOR MANAGEMENT CONSOLE MODULES" shall be defined as the
                modules which interoperate with the ISOCOR Management Console to
                allow the ISOCOR Management Console to control a LDAP connector
                built into the Join Engine and the Text Universal Connector.

        1.15    "ISOCOR STANDARD CONNECTORS" means any ISOCOR Connectors not
                listed in Exhibit C and delivered to Netscape hereunder.

        1.16    "INTERNATIONALIZATION/INTERNATIONALIZED" means 8-bit clean
                (i.e., data doesn't get corrupted due to assumptions that the
                data is 7-bit ASCII text, and therefore the 8th bit can be used
                as a flag).

        1.17    "LDAP" shall mean the Lightweight Directory Access Protocol.

        1.18    "LIMITED WARRANTY PERIOD" shall mean ninety (90) consecutive
                calendar days after date of Acceptance.

        1.19    "LICENSED PROGRAMS" shall mean all or any portion of : (a) the
                Object Code of the ISOCOR Join Engine, the Object Code of the
                ISOCOR Standard Connectors, the Object Code of the Exclusive
                Connectors, the Object Code of the Text Universal Connector, and
                the Object Code of the ISOCOR Management Console delivered to
                Netscape during the term or dates specified herein; and (b) the
                Source Code of the ISOCOR Join Engine, the Source Code of the
                Exclusive Connectors, the Source Code ISOCOR Management Console
                Modules, and the Source Code of the Text Universal Connector
                delivered to Netscape during the term or dates specified herein.

        1.20    "NETSCAPE AFFILIATES" means Actra Business Systems LLC, Novonyx,
                Inc., Navio Communications, Inc. and any corporation,
                partnership, joint venture or other entity or person Controlled
                by Netscape.


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


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        1.21    "NETSCAPE JOIN ENGINE" shall be defined as a join engine which
                is based on all or a portion of the ISOCOR Join Engine but
                which: (i) contains Netscape modifications to the user interface
                of the ISOCOR Join Engine; or (ii) is a version of the ISOCOR
                Join Engine ported to a platform other than those delivered to
                Netscape by ISOCOR hereunder; or, (iii) contains Netscape
                modifications to the ISOCOR Join Engine other than Netscape
                modifications to the wrapper, icons, help Section or about
                Section of the ISOCOR Join Engine.

        1.22    "OBJECT CODE" shall mean the machine-readable form of the
                Licensed Programs and all related Documentation.

        1.23    "PRODUCTS" shall mean any Netscape Connector or Netscape Join
                Engine which contains in whole or in part the Royalty Bearing
                Licensed Programs.

        1.24    "ROYALTY BEARING LICENSED PROGRAMS" shall mean all or any
                portion of: (a) the Object Code of the ISOCOR Join Engine, (b)
                the Object Code of the ISOCOR Standard Connectors, (c) the
                Object Code of the Exclusive Connectors, and (d) the Object Code
                of the ISOCOR Management Console delivered to Netscape during
                the term or dates specified herein and distributed by Netscape
                for general commercial use. Royalty Bearing Licensed Programs
                shall not include the Object Code of the Text Universal
                Connector, either in whole or in part, nor shall Royalty Bearing
                Licensed Programs include any Product or Royalty Bearing
                Licensed Program (i) distributed by Netscape to existing
                customers already licensed to use the Licensed Programs or
                Product and for which a Royalty has accrued to ISOCOR as
                back-up, replacement or update copies for which the existing
                customer pays nothing or only a nominal shipping and handling
                fee; (ii) copies used for training, marketing and supporting the
                Licensed Programs and/or Product, and (iii) a reasonable number
                of copies of the Licensed Programs provided at no or a nominal
                charge for marketing and promotional purposes to promote the
                sale of copies of the Licensed Programs or Product (e.g., copies
                provided to the press, demonstration or evaluation copies,
                etc.).

        1.25    "SOURCE CODE" shall mean the human-readable form that is
                required to build the binary/object code of the applicable
                Licensed Program and shall include any and all available
                necessary source code, build scripts, test source code, test
                scripts, up to date design specifications and Documentation.

        1.26    "STANDARD CONNECTORS" means Connectors developed by ISOCOR and
                not defined as Exclusive Connectors, excluding the Text
                Universal Connector. If and when available, delivery to Netscape
                of an ISOCOR Standard Connector shall be within [***] after
                ISOCOR ships any general release Standard Connector to a
                customer.

        1.27    "SPECIFICATIONS" shall mean, collectively, the Technology
                Specifications as described in Attachment A-1 and other
                Documentation for the Licensed Programs.

        1.28    "TEXT UNIVERSAL CONNECTOR" shall be defined as ISOCOR's text
                connector software which enables foreign systems/directories to
                be accessed by the ISOCOR Join Engine and which may be
                customized by writing Perl programs to connect arbitrary data
                with the Connector View. The Text Universal Connector shall
                contain, at a minimum, those features set forth in the
                Technology Specifications.

2.      GRANT OF RIGHTS

        2.1     SOURCE FORM LICENSE AND OBJECT FORM LICENSE FOR THE ISOCOR JOIN
                ENGINE, EXCLUSIVE CONNECTORS, TEXT UNIVERSAL CONNECTOR. Subject
                to the terms of this Agreement, ISOCOR


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


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                hereby grants Netscape a perpetual, worldwide, nonexclusive
                license (except if terminated under Section 8) to (i) use,
                modify, enhance, create derivative works and subsets of,
                reproduce and translate the Source Code of the ISOCOR Join
                Engine, the Source Code of the Exclusive Connectors, and the
                Source Code of the Text Universal Connector, any Object Code of
                the ISOCOR Join Engine, the Object Code of the Exclusive
                Connectors, and the Object Code of the Text Universal Connector,
                compiled or otherwise derived therefrom and any related user and
                reference Documentation delivered to Netscape hereunder,
                including, without limitation, improvements, updates and
                modifications to such Documentation delivered to Netscape
                hereunder (ii) incorporate any portion of the ISOCOR Join
                Engine, the Exclusive Connectors, the Text Universal Connector
                and related Documentation into or bundle any portion of the
                ISOCOR Join Engine, the Exclusive Connectors, and the Text
                Universal Connector and/or related Documentation with the
                Products, (iii) directly or indirectly through third parties,
                distribute (in any media or technology and by any means known or
                hereafter developed, including electronic distribution)
                standalone (either as a Product or as an ISOCOR product) or
                incorporated into or bundled with a Product, sublicense, market,
                promote, perform and display the ISOCOR Join Engine Object Code,
                the Exclusive Connectors Object Code, and the Text Universal
                Connector Object Code and related Documentation or any portion
                or portions thereof and (iv) sublicense any of the foregoing
                rights as they relate to the ISOCOR Join Engine Object Code, the
                Exclusive Connectors Object Code, and the Text Universal
                Connector Object Code and/or related Documentation and as
                otherwise provided in Section 2.9. Netscape shall be entitled to
                exercise the foregoing rights and licenses with respect to the
                Source Code of the ISOCOR Join Engine, Exclusive Connectors, and
                the Text Universal Connectors through subcontractors (on-site
                and off-site); provided, that Netscape shall not have the right
                to sublicense such rights or licenses except as described in
                Section 2.9. Any distribution by Netscape of the ISOCOR Join
                Engine Object Code, the Exclusive Connectors Object Code, the
                Text Universal Connector Object Code and related Documentation
                shall be under terms not materially less protective of the
                rights of ISOCOR than those Netscape uses for its other
                products. Netscape shall comply with all applicable laws and
                regulations in sublicensing the Exclusive Connectors, the Text
                Connectors, the Products, and related Documentation, including
                but not limited to applicable FAR and DFAR regulations.

        2.2     RIGHT OF FIRST REFUSAL. For [***] after the Netscape Join Engine
                Release Date (as defined in Section 1.4.a of Exhibit B attached
                hereto), if Netscape wishes to add a feature(s) to an Exclusive
                Connector, Netscape will notify ISOCOR in writing of its request
                to add such feature(s), and ISOCOR shall notify Netscape within
                [***] of Netscape's request whether ISOCOR will or will not
                develop and provide such feature(s). In the event ISOCOR elects
                to provide such feature(s), ISOCOR shall deliver such feature to
                Netscape at no charge no less than [***] after Netscape requests
                such feature(s). In the event that ISOCOR elects not to develop
                and deliver a feature(s) or the [***] notification period has
                elapsed (whichever is sooner), then ISOCOR shall immediately
                deliver to Netscape the Source Code to such Exclusive Connector
                (if Netscape does not have the Source Code to such Exclusive
                Connector), and Netscape shall have the right to create
                derivative works of the Source Code to such Exclusive Connector
                as described in this Section 2.2.

        2.3     OBJECT CODE LICENSE FOR STANDARD CONNECTORS AND ISOCOR
                MANAGEMENT CONSOLE. ISOCOR hereby grants Netscape a perpetual,
                worldwide, nonexclusive license (except if terminated under
                Section 8) to (i) use, reproduce, translate, market and
                distribute directly or indirectly through third parties (in any
                media, electronic format or technology and by any means known or
                hereafter developed) (a) the Object Code of the ISOCOR
                Management Console and the Object Code of the Standard
                Connectors when integrated into, bundled with, or distributed
                for use in connection solely with the Object Code of the ISOCOR
                Join Engine or the Object Code of the Netscape Join Engine, and
                (b) any user and


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


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                reference Documentation related to the Object Code of the ISOCOR
                Management Console or the Object Code of the Standard Connectors
                delivered to Netscape hereunder, including, without limitation,
                improvements, updates and modifications to such documentation
                delivered to Netscape hereunder, and any derivative works or
                subsets thereof prepared by or for Netscape; (ii) create
                derivative works and subsets of the ISOCOR Management Console
                and/or Standard Connector Documentation; and (iii) sublicense
                any of the foregoing rights, or grant any of the foregoing
                rights to its multiple tiers of distribution channels (including
                original equipment manufacturers). Any distribution by Netscape
                of the Object Code of the Standard Connectors, the Object Code
                of the ISOCOR Management Console, the Object Code of the
                Products and related Documentation shall be under terms not
                materially less protective of the rights of ISOCOR than those
                Netscape uses for its other products. Netscape shall comply with
                all applicable laws and regulations in sublicensing the Standard
                Connectors, ISOCOR Management Console, Products, and related
                Documentation including but not limited to applicable FAR and
                DFAR regulations.

        2.4     SOURCE CODE LICENSE FOR THE ISOCOR MANAGEMENT CONSOLE MODULES.
                Subject to the terms of this Agreement, Licensor hereby grants
                Netscape a perpetual, worldwide, nonexclusive license (except if
                terminated under Section 8) to (i) use, modify, enhance, create
                derivative works and subsets of, reproduce and translate the
                Source Code of the ISOCOR Management Console Modules, any Object
                Code of the ISOCOR Management Console Modules compiled or
                otherwise derived therefrom, and any related user and reference
                Documentation delivered to Netscape hereunder, including,
                without limitation, improvements, updates and modifications to
                such Documentation delivered to Netscape hereunder, (ii)
                incorporate any portion of the ISOCOR Management Console Modules
                into or bundle any portion of the ISOCOR Management Console
                Modules with the Products, (iii) directly or indirectly through
                third parties, distribute (in any media or technology and by any
                means known or hereafter developed, including electronic
                distribution) standalone (either as a Product or as an ISOCOR
                product) or incorporated into or bundled with a Product,
                sublicense, market, promote, perform and display the ISOCOR
                Management Console Modules Object Code and Documentation or any
                portion or portions thereof and (iv) sublicense any of the
                foregoing rights as they relate to the ISOCOR Management Console
                Modules Object Code and/or Documentation and as otherwise
                provided in Section 2.9. Netscape shall be entitled to exercise
                the foregoing rights and licenses with respect to the ISOCOR
                Management Console Modules Source Code through subcontractors
                and other third parties (both on-site and off-site); provided,
                that Netscape shall not have the right to sublicense such rights
                or licenses except as described in Section 2.9. Any distribution
                by Netscape of the ISOCOR Management Console Modules, Products
                and Documentation shall be under terms not materially less
                protective of the rights of ISOCOR than those Netscape uses for
                its other products. Netscape shall comply with all applicable
                laws and regulations in sublicensing the Technology, including
                but not limited to applicable FAR and DFAR regulations.

        2.5     LIMITATION ON SOURCE CODE LICENSES. Notwithstanding any term or
                condition in this Agreement and except as provided for in
                Section 2.9, Netscape is not granted a right or license to
                distribute, license, sub-license, lease, rent, re-sell, in whole
                or in part, the Source Code of any Licensed Programs.

        2.6     FIRST PRELIMINARY COPY LICENSE. Subject to the terms of this
                Agreement, ISOCOR hereby grants Netscape a perpetual, worldwide,
                nonexclusive license (except if terminated under Section 8) to
                (i) use, modify, enhance, create derivative works and subsets
                of, reproduce and translate the Source Code of the First
                Preliminary Copy (as defined in Exhibit A (3)(A)), any Object
                Code of the First Preliminary Copy, compiled or otherwise
                derived therefrom and any related user and reference
                Documentation delivered to Netscape hereunder, including,
                without limitation, improvements, updates and modifications to


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                such Documentation delivered to Netscape hereunder (ii)
                incorporate any portion of the ISOCOR First Preliminary Copy
                into or bundle any portion of the First Preliminary Copy and/or
                related Documentation with the Products, (iii) directly or
                indirectly through third parties, distribute (in any media or
                technology and by any means known or hereafter developed,
                including electronic distribution) standalone (either as a
                Product or as an ISOCOR product) or incorporated into or bundled
                with a Product, sublicense, market, promote, perform and display
                the First Preliminary Copy and related Documentation or any
                portion or portions thereof and (iv) sublicense any of the
                foregoing rights as they relate to the First Preliminary Copy
                and/or related Documentation and as otherwise provided in
                Section 2.9. Netscape shall be entitled to exercise the
                foregoing rights and licenses with respect to the Source Code of
                the First Preliminary Copy through subcontractors (on-site and
                off-site); provided, that Netscape shall not have the right to
                sublicense such rights or licenses except as described in
                Section 2.9. Any distribution by Netscape of the ISOCOR First
                Preliminary Copy and related Documentation shall be under terms
                not materially less protective of the rights of ISOCOR than
                those Netscape uses for its other products. Netscape shall
                comply with all applicable laws and regulations in sublicensing
                the First Preliminary Copy, the Products, and related
                Documentation, including but not limited to applicable FAR and
                DFAR regulations.

        2.7     OUTSOURCING. Netscape may use or operate all or any portion of
                the Object Code of the Licensed Programs or the Object Code of
                the Products for a third party who has a valid sublicense
                granted hereunder.

        2.8     TRADEMARK LICENSE. Netscape and its channels of distribution may
                use at their discretion, and is granted during the term hereof a
                nontransferable, nonexclusive and restricted license (with a
                right to sublicense to distribution channels ) the marks
                "ISOCOR" and "ISOCOR MetaConnect" (collectively, the "Marks") in
                all advertising, marketing, technical, packaging and other
                materials related to the Products for distribution under this
                Agreement. Netscape shall not use the Marks in any country in
                which their connotation is offensive and will consult with
                ISOCOR as to the foreign translation of the Marks so that ISOCOR
                can ensure uniformity of use. All use of the Marks shall inure
                to ISOCOR's benefit. Neither Netscape nor its distribution
                channels shall register any ISOCOR trademarks, or trademarks,
                trade names or domain names confusingly similar to ISOCOR
                trademarks, trade names or domain names without ISOCOR's express
                prior written consent. Upon ISOCOR's request from time to time,
                Netscape shall provide ISOCOR with copies of any Products
                bearing the Marks. If Netscape uses the Marks in a manner which
                jeopardizes ISOCOR's ownership of such logos or trademarks,
                Netscape will use commercially reasonable efforts to promptly
                cease using the Marks in such manner, but Netscape shall not be
                required to destroy or recall any Product. Netscape further
                agrees not to use any Marks on or in connection with any
                products or services that are or could be deemed by ISOCOR, in
                its reasonable judgment, to be obscene, pornographic,
                disparaging of ISOCOR or of its products, or otherwise in poor
                taste, or that are themselves unlawful or whose purpose is to
                encourage unlawful activities by others. Netscape agrees not to
                obtain or attempt to obtain by any manner whatsoever any right,
                title or interest in or to any of the Marks or any confusingly
                similar mark. Any use of the Marks beyond the scope of this
                Section 2.8 shall constitute infringement and material breach.
                Netscape expressly agrees that any breach or threatened breach
                of this Section 2.8 may cause ISOCOR irreparable injury for
                which there may be no adequate remedy at law, and that in
                addition to any other remedies available, ISOCOR shall therefore
                be entitled to seek injunctive relief without the necessity of
                proving actual damages.

        2.9     AFFILIATE SUBLICENSES. Netscape may grant its Affiliates a
                sublicense to the Licensed Programs and Documentation equal in
                scope to, and subject to the same limitations as, the licenses
                granted hereunder by ISOCOR to Netscape. In the event that
                Netscape divests its interests in an Affiliate such that
                Netscape no longer controls such Affiliate, then any




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                sublicenses granted to such Affiliate with respect to the Source
                Code as provided under this Agreement shall terminate.

        2.10    NO OBLIGATION. Notwithstanding anything to the contrary in this
                Agreement, nothing herein shall require Netscape to use or
                distribute any of the Licensed Programs with any Product.
                Notwithstanding anything to the contrary in this Agreement,
                nothing herein shall prohibit ISOCOR in any manner from using,
                developing, marketing, licensing or otherwise disposing of the
                Licensed Programs or Documentation or embodied concepts therein
                anywhere in the world; nor shall anything be construed to grant
                to Netscape, or any Netscape sublicensees, any rights in or to
                any other present or future products of ISOCOR whether or not
                similar to the Licensed Programs or related Documentation.

        2.11    EXCLUSIVITY. During the Exclusivity Period Netscape shall not
                create a connector which directly competes with the Exclusive
                Connectors. For purposes of this Section 2.11 a connector which
                "directly competes" with an Exclusive Connector shall mean a
                connector that operates on the same foreign directory as such
                Exclusive Connector, e.g. a connector which operates on cc:Mail,
                Notes, Exchange, and the other directories as listed in Exhibit
                C.

        2.12    MARKETING. The parties agree to participate in the marketing
                activity set forth in Exhibit D attached hereto.

3.      PROPRIETARY RIGHTS. ISOCOR retains title to the Licensed Programs and
        related Documentation. ISOCOR shall have no ownership interest in
        Netscape's products (including the Products), other than the rights in
        the Licensed Programs and related Documentation described in the
        preceding sentence. Title to any modifications, enhancement or
        improvements to, or derivative works of, the Licensed Programs or
        Documentation that are developed by or for a party shall be reserved to
        and remain with the party that developed or had developed such
        modification, enhancement, improvement or derivative work.

4.      MAINTENANCE, SUPPORT AND TRAINING

        4.1     SUPPORT OF NETSCAPE. ISOCOR agrees to provide Netscape with the
                Support with respect to the Licensed Programs and Documentation
                as further described in Exhibit B.

        4.2     TRAINING OF NETSCAPE. ISOCOR shall provide training to Netscape
                employees, independent contractors and consultants in accordance
                with the provisions set forth in Exhibit B.

        4.3     STATUS REPORTS AND MEETINGS. Beginning on the Effective Date and
                ending when Netscape Accepts the ISOCOR Join Engine, ISOCOR
                shall provide Netscape, no less than once per week, a written
                report which provides ISOCOR's current status with respect to
                ISOCOR's development of the Licensed Programs, including but not
                limited to ISOCOR's progress in relation to its then-current
                product release schedules. Any information in such written
                reports shall be deemed Proprietary Information (as defined in
                Section 9 below) without the need for marking such reports as
                proprietary.

5.      PAYMENTS AND ACCOUNTING

        5.1     PAYMENTS. Netscape agrees to make payments to ISOCOR as provided
                in Exhibit B hereto.

        5.2     TAXES. All prices are in U.S. Dollars and are exclusive of any
                applicable taxes. The prices in this Agreement are for the
                Licensed Programs and related Documentation only.


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                Netscape shall be responsible for sales or use taxes resulting
                from the granting of the licenses hereunder by ISOCOR to
                Netscape with respect to the Licensed Programs, or Netscape
                shall provide ISOCOR with an appropriate exemption certificate.
                Netscape shall be responsible for all other taxes, assessments,
                permits and fees, however designated which are levied upon this
                Agreement or the Licensed Programs, except taxes based upon
                ISOCOR's net income with respect to the Licensed Programs and
                Documentation. Each party shall cooperate with the other in
                minimizing any applicable tax.

        5.3     AUDIT. Netscape shall keep proper records and books of accounts
                and proper entries therein relating to use and sublicense of the
                Licensed Programs and Documentation. ISOCOR shall have the
                right, no more than once every year during normal business hours
                upon at least thirty (30) days prior notice, to audit, by a
                nationally recognized independent public accounting firm, the
                relevant records of Netscape to verify compliance with the
                provisions of this Agreement. The audit shall be conducted at
                ISOCOR's expense, and the results of such audit will be deemed
                Proprietary Information (as defined in Section 9 below) without
                the need for marking such information. If such audit finds that
                in excess of [***] of such amounts for any Netscape Fiscal
                Quarter are overdue, then Netscape shall pay for the costs of
                such audit.

6.      WARRANTIES AND INDEMNIFICATION

        6.1     TITLE. ISOCOR warrants that (i) it has the right to grant the
                licenses as set forth in this Agreement, (ii) such licenses do
                not infringe on any third parties' proprietary or personal
                rights, (iii) it owns or controls all rights, title and interest
                in and to the Licensed Programs and Documentation or has rights
                to sublicense the Licensed Programs and Documentation as
                provided herein, (iv) Netscape shall not be obligated to pay any
                fees or royalties for use of the Licensed Programs or
                Documentation other than as specifically set forth in this
                Agreement, and (v) there are no pending or threatened lawsuits
                concerning any aspect of the Licensed Programs or Documentation.
                If ISOCOR becomes aware of any pending or threatened lawsuit
                concerning any aspect of the Licensed Programs or Documentation,
                ISOCOR shall notify Netscape and provide Netscape with all
                information reasonably related thereto.

        6.2     NON-INFRINGEMENT. Without limiting Netscape's rights under
                Section 6.7, should the Licensed Programs or Documentation
                become, or in ISOCOR's opinion be likely to become, the subject
                of any infringement claim or suit, ISOCOR shall, at its option,
                (i) procure for Netscape the right to continue distributing the
                Licensed Programs and Documentation, as well as the right for
                Netscape and its customers to continue use of the Licensed
                Programs and Documentation, while maintaining its functionality,
                or (ii) modify the Licensed Programs or Documentation such that
                it no longer infringes the proprietary rights of any third
                party, while maintaining the functionality, look and feel of the
                Products.

        6.3     PERFORMANCE. During the Limited Warranty period, ISOCOR warrants
                only to Netscape that (i) the media on which the Licensed
                Programs and Documentation are delivered will be free of defects
                in material and workmanship, (ii) the Licensed Programs when
                properly installed will function substantially in accordance
                with the Specifications, and (iii) the Documentation shall be
                accurate in all material respects. In the case of a breach of
                the warranties in this Section 6.3 (and in addition to any
                rights Netscape may have), ISOCOR shall repair or replace
                nonconforming, unsuitable or inaccurate Licensed Programs or
                Documentation within a reasonable period of time of notice of
                such condition.

        6.4     EXPORT. ISOCOR shall inform Netscape and keep Netscape apprised
                of the export approval status of the Licensed Programs and must
                promptly inform Netscape of any


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       8
<PAGE>   9
                cryptographic technologies used or embedded within the Licensed
                Programs, and of any associated international restrictions.

        6.5     YEAR 2000. ISOCOR warrants that the Licensed Programs is Year
                2000 Compliant. "YEAR 2000 COMPLIANT" shall mean the Licensed
                Programs complies with the following:

                a)      General Integrity: No value for the current date will
                        interrupt normal operation: the system on which the
                        Licensed Programs operates returns the correct date
                        accurate to century in response to a request for current
                        date, the Licensed Programs correctly provides date
                        output and performs calculations on dates or portions of
                        dates, and the Licensed Programs is unaffected by any
                        value returned;

                b)      Date Integrity: Correct results are returned in the
                        operation of all legal, arithmetic, logical and calendar
                        operations of dates that span century marks;

                c)      Explicit Century: The Licensed Programs's internal date
                        storage format explicitly includes the century and
                        reporting formats allow date representations in four
                        digit format;

                d)      Implicit Century: On encountering data that does not
                        include the century either from transaction input or
                        from an external data source, the century value is
                        unambiguously inferred by the Licensed Programs.

                The Year 2000 Warranty in this Section 6.5 shall not apply to
                the extent that performance is prevented by third party software
                (including operating systems), hardware, or by unauthorized
                modifications made to the Licensed Programs, provided that such
                third party software, hardware or unauthorized modification is
                the cause of the non-performance. In the case of a breach of the
                warranty described in this Section 6.5, ISOCOR shall use best
                efforts to modify the Licensed Programs such that the Licensed
                Programs is Year 2000 Compliant. If ISOCOR is unable to make
                such modifications within a reasonable period of time (as
                determined by Netscape in its reasonable discretion), then
                Netscape may terminate this Agreement and receive a full refund
                of all payments made to ISOCOR hereunder.

        6.6     DISCLAIMER. THE WARRANTIES PROVIDED BY ISOCOR HEREIN ARE THE
                ONLY WARRANTIES PROVIDED BY ISOCOR WITH RESPECT TO THE LICENSED
                PROGRAMS AND DOCUMENTATION. SUCH WARRANTIES ARE IN LIEU OF ALL
                OTHER WARRANTIES BY ISOCOR, EXPRESS OR IMPLIED, INCLUDING ANY
                IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
                PURPOSE, WITH RESPECT TO THE LICENSED PROGRAMS AND
                DOCUMENTATION.

        6.7     INDEMNITY. ISOCOR agrees to defend, indemnify and hold Netscape
                harmless from all liabilities, costs, damages and expenses
                (including settlement costs and attorneys' fees) arising from
                third party claims alleging that Netscape's exercise of its
                rights to the Licensed Programs or Documentation granted by
                ISOCOR hereunder infringes any trademark, patent, copyright,
                trade secret or other proprietary right of any third party. In
                connection with such indemnification, Netscape will (i) promptly
                notify ISOCOR in writing of any such claim and grant ISOCOR
                control of the defense and all related settlement negotiations,
                and (ii) cooperate with ISOCOR, at ISOCOR's expense, in
                defending or settling such claim; provided that if any
                settlement results in any ongoing liability to, or prejudices or
                detrimentally impacts Netscape, and such obligation, liability,
                prejudice or impact can reasonably be expected to be material,
                then such settlement shall require Netscape's written consent.
                In connection with any such claim, Netscape may have its own
                counsel in attendance at all public interactions and substantive
                negotiations at its own cost and expense.


                                       9
<PAGE>   10
7.      LIMITATION OF LIABILITY. EXCEPT FOR ISOCOR'S OBLIGATIONS AND LIABILITY
        UNDER SECTION 6.7, IN NO EVENT WILL EITHER PARTY BE LIABLE FOR ANY LOST
        PROFITS OR ANY FORM OF INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
        DAMAGES OF ANY CHARACTER FROM ANY CAUSES OF ACTION OF ANY KIND WITH
        RESPECT TO THIS AGREEMENT OR THE LICENSED PROGRAMS LICENSED HEREUNDER,
        WHETHER ARISING IN TORT (INCLUDING NEGLIGENCE), CONTRACT, OR OTHERWISE,
        EVEN IF IT HAS BEEN INFORMED IN ADVANCE OF THE POSSIBILITY OF SUCH
        DAMAGES.

8.      TERM AND TERMINATION

        8.1     TERM. Unless earlier terminated pursuant to the provisions of
                Subsections 8.2, the term of this Agreement shall be perpetual.

        8.2     TERMINATION FOR CAUSE. Either party shall have the right to
                terminate this Agreement upon a material default by the other
                party of any of its material obligations under this Agreement,
                unless within thirty (30) calendar days after written notice of
                such default such party remedies such default. Failure to pay
                undisputed moneys owed to ISOCOR or any breach of
                confidentiality as described in this Agreement, is an example of
                a material default of the obligations under this Agreement, and
                shall be grounds for termination of this Agreement by the
                non-breaching party at the non-breaching party's sole discretion
                if such breach is not cured in accordance with this Section 8.2.

        8.3     RIGHTS UPON TERMINATION OR EXPIRATION. Upon expiration or
                termination of this Agreement, except for termination by ISOCOR
                for Netscape's failure to pay ISOCOR any undisputed amounts due
                under this Agreement or Netscape's willful breach of Section 9.2
                of this Agreement, Netscape shall produce a version of the
                Product(s) which does not include the Licensed Programs [***].
                In the event of ISOCOR's termination of this Agreement due to
                Netscape's failure to pay ISOCOR any undisputed amounts due
                under this Agreement or due to Netscape's willful violation of
                Section 9.2, the "End Date" shall be [***]. Following
                termination or expiration for any reason, Netscape and its
                distribution channels shall be entitled to continue to exercise
                the rights granted hereunder with respect to all versions of the
                Products shipped prior to the End Date, provided that Netscape
                shall cease producing products which incorporate the Licensed
                Programs into any Product after the End Date. In addition,
                following expiration or termination Netscape may also retain a
                reasonable number of copies of the Source Code, Object Code and
                Documentation to provide maintenance and support to
                sublicensees. [***]

        8.4     SURVIVAL AFTER TERMINATION OR EXPIRATION

                8.4.1   SUBLICENSES. All sublicenses to the Licensed Programs
                        which are properly granted shall survive any termination
                        or expiration of this Agreement. "Properly granted
                        sublicenses" are those sublicenses which are granted
                        under this Agreement and for which ISOCOR has accrued or
                        been paid Royalties (if applicable) as provided herein.

                8.4.2   PROVISIONS OF AGREEMENT. Sections 1, 2, 3, 5, 6, 8, 9
                        and 10 shall survive the termination or expiration of
                        this Agreement for any reason. Provisions of other


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       10
<PAGE>   11
                        Sections and Subsections which, by their nature, must
                        remain in effect beyond the termination or expiration of
                        this Agreement shall survive.

9.      CONFIDENTIALITY

        9.1     CONFIDENTIAL INFORMATION. Each party (the "RECEIVING PARTY")
                understands that the other party (the "DISCLOSING PARTY") has
                disclosed or may disclose information of a confidential nature
                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 ("PROPRIETARY INFORMATION"). All Proprietary
                Information disclosed in tangible form by the Disclosing Party
                shall be marked "confidential" or "proprietary" and all
                Proprietary Information disclosed orally or otherwise in
                intangible form by the Disclosing Party shall be designated as
                confidential or proprietary at the time of disclosure. The
                Source Code to the Licensed Programs and the Source Code to the
                Documentation shall be deemed Proprietary Information without
                the need to mark them as such.

        9.2     DISCLOSURE AND USE. The Receiving Party agrees (i) to hold the
                Disclosing Party's Proprietary Information in confidence and to
                take all necessary precautions to protect such Proprietary
                Information (including, without limitation, all precautions the
                Receiving Party employs with respect to its own confidential
                materials), (ii) not to divulge any such Proprietary Information
                or any information derived therefrom to any third person, except
                independent contractors under an obligation of confidentiality
                and with a need to know for purposes authorized under this
                Agreement, (iii) not to make any use whatsoever at any time of
                such Proprietary Information except as authorized under this
                Agreement, and (iv) not to remove or export any such Proprietary
                Information from the country of the Receiving Party except as
                may be allowed by applicable export laws. The Receiving Party
                shall limit the use of and access to the Disclosing Party's
                Proprietary Information to the Receiving Party's employees,
                attorneys and independent contractors under an obligation of
                confidentiality and restricted use who need to know such
                Proprietary Information for the purposes authorized under this
                Agreement. The Receiving Party shall treat the Proprietary
                Information with at least the same degree of care and protection
                as it would use with respect to its own proprietary information.
                The foregoing obligations shall survive for a period of five (5)
                years from the date of disclosure of the Proprietary
                Information. Without granting any right or license, the
                Disclosing Party agrees that the foregoing shall not apply with
                respect to information that the Receiving Party can establish
                (i) is in the public domain and is available at the time of
                disclosure or which thereafter enters the public domain and is
                available, through no improper action or inaction by the
                Receiving Party or any affiliate, agent or employee, or (ii) was
                in its possession or known by it prior to receipt from the
                Disclosing Party, or (iii) was rightfully disclosed to it by
                another person without restriction, or (iv) is independently
                developed by the Receiving Party without access to such
                Proprietary Information, or (v) is required to be disclosed
                pursuant to any statutory or regulatory authority, provided the
                Disclosing Party is given prompt notice of such requirement and
                the scope of such disclosure is limited to the extent possible,
                or (vi) is required to be disclosed by a court order, provided
                the Disclosing Party is given prompt notice of such order and
                provided the opportunity to contest it.

        9.3     INDEPENDENT DEVELOPMENT. The terms of this Agreement shall not
                be construed to limit either party's right to independently
                develop or acquire products without use of the other party's
                Proprietary Information or to license or market any products.
                Further, Proprietary Information as defined in Section 9.1 above
                shall not include the Residuals resulting from access to such
                Proprietary Information. The term "RESIDUALS" means information
                in intangible form which may be retained in the unaided memories
                of Receiving Party's


                                       11
<PAGE>   12
                employees or independent contractors who have had access to the
                information. An employee's or contractor's memory will be
                considered to be unaided if the employee has not intentionally
                memorized the Proprietary Information for the purpose of
                retaining and subsequently using or disclosing it. Neither party
                shall have any obligation to limit or restrict the assignment of
                such persons or to pay royalties for any work resulting from the
                use of Residuals. However, the foregoing shall not be deemed to
                grant to either party a license under the other party's
                copyrights or patents.

        9.4     RETURN OF PROPRIETARY INFORMATION. Upon any termination or
                expiration of this Agreement each party will destroy, or return
                to the other party, all tangible copies of the other party's
                Proprietary Information.

        9.5     CONFIDENTIALITY OF AGREEMENT. Each party agrees that the terms
                of this Agreement shall be deemed Proprietary Information of the
                other party, provided that in addition to the permitted
                disclosures under section 9.2, either party may disclose the
                terms of this Agreement (i) if required to do so by law or
                generally accepted accounting principles, (ii) as required to
                assert its rights hereunder, and (iii) to its own directors,
                employees, attorneys, accountants, and other advisors on a "need
                to know" basis and under an obligation of confidentiality no
                less stringent than set forth herein. Each party agrees that the
                Disclosing Party will be given prompt notice of any disclosure
                made pursuant to clause (i) or (ii) above, and that any such
                disclosure shall be limited to the extent possible. In addition,
                Netscape may disclose the terms of this Agreement or matters
                relating thereto to its Affiliates.



10.     SOURCE CODE ESCROW. Notwithstanding anything contained in Section 2 to
        the contrary, ISOCOR grants Netscape a license to deposit the Source
        Code to the Licensed Programs in escrow account(s) for the benefit of
        Netscape's licensees of the Object Code, provided Netscape source code
        is deposited in such escrow and provided the Source Code is subject to
        the same release conditions and restrictions on use as the Netscape
        source code and provided that the Source Code shall only be used for
        support and maintenance of Netscape's customers.

11.     GENERAL

        11.1    GOVERNING LAW. This Agreement shall be subject to and governed
                in all respects by the statutes and laws of the State of
                California without regard to the conflicts of laws principles
                thereof. The Superior Court of Santa Clara County and/or the
                United States District Court for the Northern District of
                California shall have exclusive jurisdiction and venue over all
                controversies in connection herewith, and each party hereby
                consents to such exclusive and personal jurisdiction and venue.

        11.2    ENTIRE AGREEMENT. This Agreement, including the exhibits and
                attachments referenced on the signature page hereto, constitutes
                the entire Agreement and understanding between the parties and
                integrates all prior discussions between them related to its
                subject matter. No modification of any of the terms of this
                Agreement shall be valid unless in writing and signed by an
                authorized representative of each party.

        11.3    ASSIGNMENT. This Agreement is not assignable by either party
                without the prior written consent of the other party; provided,
                however, that either party may assign this Agreement in
                connection with any merger, acquisition, reorganization, sale of
                substantially all of the assets or stock of that party or any
                similar event without the prior written consent of the other
                party. This Agreement shall apply to and bind any successor or
                assigns of the parties hereto.


                                       12
<PAGE>   13
        11.4    NOTICES. All notices required or permitted hereunder shall be
                given in writing addressed to the respective parties as set
                forth below and shall either be (i) personally delivered, (ii)
                transmitted by postage prepaid certified mail, return receipt
                requested, or (iii) transmitted by nationally-recognized private
                express courier for the next business day overnight delivery,
                and shall be deemed to have been given on the date of receipt if
                delivered personally, or two (2) days after deposit via
                overnight express courier, or on receipt via pre-paid certified
                mail, whichever is sooner. Either party may change its address
                for purposes hereof by written notice to the other in accordance
                with the provisions of this Subsection. The addresses for the
                parties are as follows:

<TABLE>
<S>                                                   <C>
        ISOCOR:                                       Netscape:
        ISOCOR                                        Netscape Communications Corporation
        3420 Ocean Park Blvd.                         501 East Middlefield Road
        Santa Monica, CA  90405                       Mountain View, CA 94043
        -------------------------------               Fax: (415) 528-4123
        Attn: Vice-President of Administration        Attn: General Counsel
</TABLE>

        11.5    FORCE MAJEURE. Neither party will be responsible for any failure
                to perform its obligations under this Agreement due to causes
                beyond its reasonable control, including but not limited to acts
                of God, war, riot, embargoes, acts of civil or military
                authorities, fire, floods or accidents.

        11.6    WAIVER. The waiver, express or implied, by either party of any
                breach of this Agreement by the other party will not waive any
                subsequent breach by such party of the same or a different kind.

        11.7    HEADINGS. The headings to the Sections and Subsections of this
                Agreement are included merely for convenience of reference and
                shall not affect the meaning of the language included therein.

        11.8    INDEPENDENT CONTRACTORS. The parties acknowledge and agree that
                they are dealing with each other hereunder as independent
                contractors. Nothing contained in this Agreement shall be
                interpreted as constituting either party the joint venturer,
                employee or partner of the other party or as conferring upon
                either party the power of authority to bind the other party in
                any transaction with third parties.

        11.9    SEVERABILITY. In the event any provision of this Agreement is
                held by a court or other tribunal of competent jurisdiction to
                be unenforceable, such provision shall be reformed only to the
                extent necessary to make it enforceable, and the other
                provisions of this Agreement will remain in full force and
                effect.

        11.10   COUNTERPARTS. This Agreement may be executed in two or more
                counterparts, each of which shall be deemed an original, but all
                of which together shall constitute one and the same instrument.
                For purposes hereof, a facsimile copy of this Agreement,
                including the signature pages hereto shall be deemed to be an
                original. Notwithstanding the foregoing, the parties shall
                deliver original execution copies of this Agreement to one
                another as soon as practicable following execution thereof.

        11.11   DISPUTE RESOLUTION. Any dispute hereunder will be negotiated
                between the parties commencing upon written notice from one
                party to the other. Settlement discussions and materials will be
                confidential and inadmissible in any subsequent proceeding
                without both parties' consent. If the dispute is not resolved by
                negotiation within 45 days following such notice, the parties
                will refer the dispute to non-binding mediation conducted by
                JAMS/EndDispute in Santa Clara County, California (the "Venue").
                The parties will share the costs of mediation. If the dispute is
                not resolved after 45 days of 


                                       13
<PAGE>   14
                mediation, the parties will refer the dispute to binding
                arbitration by JAMS/EndDispute in the Venue. The results of any
                arbitration will be final and non-appealable, except that either
                party may petition any court of competent jurisdiction to review
                any decision relating to intellectual property matters
                (including the scope of license rights), vacating or modifying
                erroneous conclusions of law or findings of fact not supported
                by substantial evidence. The arbitrator may fashion any legal or
                equitable remedy except punitive or exemplary damages, which
                both parties waive. The arbitrator will render a written
                decision, which may be entered in and enforced by any court of
                competent jurisdiction in the Venue, but which will have no
                preclusive effect in other matters involving third parties. The
                losing party will pay the costs of the arbitration and the
                reasonable legal fees and expenses of the prevailing party, as
                determined by the arbitrator. The parties will jointly pay
                arbitration costs pending a final allocation by the arbitrator.
                At any point in the dispute resolution process, either party may
                seek injunctive relief preserving the status quo pending the
                outcome of that process. Except as noted, the parties waive any
                right to judicial process. California law, without regard to its
                conflict-of-law provisions, will govern this Agreement. The U.S.
                Arbitration Act and JAMS/EndDispute rules will govern the
                arbitration process. Absent fraudulent concealment, neither
                party may raise a claim more than 3 years after it arises or any
                shorter period provided by applicable statutes of limitations.

ISOCOR:                               NETSCAPE:

ISOCOR                                NETSCAPE COMMUNICATIONS CORPORATION

By: /s/ PAUL GIGG                     By: /s/ JOHN M. PAUL
    ------------------------              -------------------------------------
Print Name: PAUL GIGG                 Print Name: JOHN M. PAUL
            ----------------                      -----------------------------
Title:  CEO                           Title:  Senior Vice President & GM
        --------------------                  ---------------------------------



Effective Date:  30 SEPTEMBER 1998                    REVIEWED BY
                                                      NETSCAPE LEGAL
Exhibit A:  Licensed Programs and Products
                                                      Initial CLC
Attachment A-1:  Licensed Program Specifications              -----------------

Exhibit B:  Payments and Support

Attachment B1:  Support Obligations

Exhibit C:  Exclusive Connectors

Exhibit D:  Marketing

Exhibit E:  Documentation and Test Cases to be
Delivered to Netscape

Exhibit F:  Minimum Test Criteria for
Acceptance Test

                                       14
<PAGE>   15



                                    EXHIBIT A
                         LICENSED PROGRAMS AND PRODUCTS

1.      LOCALIZATION/INTERNATIONALIZATION. The Licensed Programs will be
        Internationalized as defined in Section 1 of this Agreement. If any
        version of the Licensed Programs delivered hereunder is not an
        Internationalized version of the Licensed Programs, Netscape shall have
        the right, at its option, to declare such failure a material breach of
        the Agreement. Subject to ISOCOR's ownership rights in the unmodified
        Licensed Programs, Netscape shall own any localized portion of the
        Licensed Programs ("LOCALIZED VERSION") produced by Netscape; provided
        that Netscape's rights to reproduce and distribute any Localized Version
        shall be coterminous with Netscape's rights to reproduce and distribute
        the Licensed Programs.

2.      ACCEPTANCE. Prior to delivering the Acceptance Candidates to Netscape,
        ISOCOR shall conduct quality assurance testing of the Acceptance
        Candidates (at least to the same extent as ISOCOR uses for its own
        products), which testing shall be run using Netscape Directory Server
        (version 3.1 or later) for all Lightweight Directory Access Protocol
        directory storage, to ensure that the Acceptance Candidates operate in
        accordance with the Specifications, including quality assurance testing
        to ensure that the Acceptance Candidates are [***]. In accordance with
        the delivery schedule set forth in this Exhibit A below, ISOCOR shall
        deliver to Netscape, for each delivery set forth in the delivery
        schedule, the appropriate technology (i.e. Acceptance Candidates or
        other pieces of the Licensed Programs) and the documentation and test
        cases listed in Exhibit E attached hereto.

        Within [***] after the delivery of an Acceptance Candidate (the date of
        delivery, the "Delivery Date"), Netscape or its designee shall test the
        Licensed Programs according to the Acceptance Test to determine, in
        Netscape's reasonable discretion, whether the Licensed Programs perform
        according to the Specifications. In the event Netscape accepts the
        Licensed Programs, Netscape shall provide ISOCOR with written notice
        that Netscape has accepted the Licensed Programs within [***] after the
        Delivery Date. In the event Netscape rejects the Licensed Programs due
        to failing the Acceptance Test, Netscape or its designee shall notify
        ISOCOR of rejection within [***] after the Delivery Date, and ISOCOR
        shall redeliver the corrected Licensed Programs or appropriate bug
        fixes, patches or workarounds as soon as commercially practicable, but
        in any event no later than [***] after the date Netscape or its designee
        provided ISOCOR with notice of rejection. In the event ISOCOR does not
        redeliver the Licensed Programs within the time frame set forth in the
        preceding sentence or Netscape again rejects the Licensed Programs,
        Netscape may request that ISOCOR correct and redeliver the Licensed
        Programs in accordance with the procedure set forth above until Netscape
        accepts the Licensed Programs, or Netscape may terminate this Agreement.
        In the event that Netscape does not provide notice of acceptance or
        rejection within [***] after the Delivery Date, then Netscape shall be
        deemed to have accepted such Acceptance Candidate or the Second
        Preliminary Copy.

3.      DELIVERY.

        A.  No later than [***], ISOCOR shall deliver to Netscape a preliminary 
            copy of the available Source Code to the Join Engine, the Text
            Universal Connector and the ISOCOR Management Console Modules
            ("First Preliminary Copy"). ISOCOR shall also deliver with the First
            Preliminary Copy any available documentation and updated
            specifications for the configuration schema of the ISOCOR Join
            Engine, Text Universal Connector and ISOCOR Management Console,
            which shall contain, at a minimum, the Documentation listed in
            Exhibit E attached hereto. Netscape acknowledges that ISOCOR is
            currently building the ISOCOR Join Engine and Text Universal
            Connector, and that the First Preliminary Copy will not contain all
            the features listed in the Specifications but shall be the most
            current version of the ISOCOR Join Engine and Text Universal
            Connector at the time of delivery. Such First Preliminary Copy shall
            not be the version of the ISOCOR Join Engine, Text Universal


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       15

<PAGE>   16

         Connector and ISOCOR Management Console which Netscape tests for
         acceptance as described in Section 1 of this Exhibit A above.

      B. No later than [***], ISOCOR shall delivery to Netscape a second
         preliminary copy of the available Source Code to the Join Engine, the
         Text Universal Connector and the ISOCOR Management Console Modules, and
         the Object Code to the Management Console ("Second Preliminary Copy").
         ISOCOR shall also deliver to Netscape any available documentation and
         updated specifications for the configuration schema of the Technology,
         which shall contain, at a minimum, the documentation listed in Exhibit
         E attached hereto. Such Second Preliminary Copy shall not be the
         version of the Licensed Programs which Netscape tests for acceptance as
         described in Section 2 above.

      C. ISOCOR shall deliver to Netscape a feature complete production version
         of the Acceptance Candidates on or before [***]. The Acceptance
         Candidate shall contain, at a minimum, the features listed in the
         Specifications. Netscape will test the Acceptance Candidate in
         accordance with the acceptance testing procedures set forth in Section
         2 of this Exhibit A.

      D. ISOCOR shall deliver to Netscape the Source Code and Object Code of the
         Exclusive Connectors no later than [***] after ISOCOR first delivers a
         non-beta version of the applicable Exclusive Connector to an end user
         or customer, but in no case shall a delivery of the Source Code and
         Object Code of an Exclusive Connector be later than the delivery dates
         listed in Exhibit C for the applicable Exclusive Connector. If ISOCOR
         fails to deliver an Exclusive Connector(s) within the earlier of (1)
         the [***] frame stated above, or (2) the delivery date stated for the
         applicable Exclusive Connector in Exhibit C, then either (i) such
         Exclusive Connector(s) shall be deemed a Standard Connector (if
         delivered to Netscape by ISOCOR) and will not be subject to the
         exclusivity provisions set forth in Section 2.10 of this Agreement, or
         (ii) Netscape may, at its option, develop a connector for such foreign
         directory, which will not be subject to the exclusivity provisions set
         forth in Section 2.10 of this Agreement. Late delivery of an Exclusive
         Connector(s) to Netscape shall not be considered a material breach of
         this Agreement.

      E. In the event that Netscape elects to have the [***]. Exclusive
         Connectors ported to other platforms not offered by ISOCOR, Netscape
         shall notify ISOCOR of the election and provide detailed performance
         and functional specifications. ISOCOR and Netscape shall then make
         commercially reasonable efforts to negotiate a mutually agreeable
         schedule and design specification within [***] from the notification.
         If ISOCOR and Netscape mutually agree on a schedule and design
         specification within such time frame, and ISOCOR delivers to Netscape
         such [***] Exclusive Connector(s) within a reasonable time, then such
         [***] Exclusive Connector(s) shall be deemed an Exclusive Connector for
         Royalty purposes. In the event ISOCOR and Netscape do not reach
         agreement on a schedule and design specification, or if ISOCOR fails to
         deliver such [***] Exclusive Connector to Netscape within a reasonable
         time, then Netscape can [***] Exclusive Connectors to such platform not
         offered by ISOCOR with such ported platforms considered a "[***]
         Exclusive Connectors" as described in Section 1.3 of Exhibit B for
         royalty purposes.


*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       16
<PAGE>   17



                                 ATTACHMENT A-1
                            TECHNOLOGY SPECIFICATIONS

                               ISOCOR METACONNECT
                         PRODUCT FEATURE SPECIFICATIONS


INTRODUCTION

This document will serve as the requirements document for Features expected to
be present within the MetaConnect product (ISOCOR engineering project name:
Atlas) as delivered to Netscape by ISOCOR.

FEATURE DESCRIPTIONS

General Requirements

    o   DIRECTORY SERVER INDEPENDENCE

        o       The product will be able to use Netscape Directory Server 3.1,
                without extensions, to store configuration, the Meta View and
                the connector views. It will also be able to use other [***].

    o   NAMESPACE JOIN

        o       The Join engine will be able to use a configurable sequence of
                searches for automatically joining a new entry into the
                MetaView. o The Join engine will provide a means to allow
                administrators to manually join entries where the automatic join
                failed.

    o   MANAGEMENT CONSOLE GUI

        o       The Join Admin GUI will be a [***] UI.

        o       The Join Admin GUI will support multiple simultaneous join
                administrators for manual join purposes.

    o   REMOTE ADMINISTRATION

        o       The product will provide the ability to manage the join process
                remotely from a separate computer on an IP network. 

        o       There will be a single level of administrative privilege from 
                the management console i.e. the management console will not 
                provide any facilities for different levels of authority. 
                Delegated administration for different levels of control may be
                possible through directory access control privilege i.e. the
                configuration for directory connectivity in the management
                console may be able to control what an individual operator is
                allowed to see and do depending on the particular directory's
                access control functionality.

    o   MULTIPLE NAMESPACE OWNERS

        o       The join engine will allow multiple connected directories and
                databases to create and own entries in the meta directory. NOTE:
                each entry can only have one "owner" for it's naming attribute
                and only the owner can delete the entry, the other attributes
                can be owned by any of the connected directories.

    o   [***] ONLY

        o       The join engine, and management console will be developed for
                the [***]. The initial release will have connectors that will
                only run on the [***] but there will be no architectural
                limitation to developing connectors on other operating system
                platforms. For subsequent releases, each connector will be
                developed for the most suitable platform.

    o   LICENSE KEY ACTIVATION

        o       The MetaConnect product components will each be subject to
                license key activation as per ISOCOR's current standard product
                offerings. This feature could be 



*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       17
<PAGE>   18

                deactivated for use in OEM opportunities but will require extra 
                engineering effort that will not be addressed for the first 
                release.

    o   OPEN SCRIPTING

        o       The MetaConnect product will support the use of Perl as a
                scripting language for customization. In particular, Perl will
                be used to support custom dn, attribute name and attribute value
                mapping in the Join Engine. 

        o       The scripting capability will be available in both operational
                directions, from Connector to Join Engine and from Join Engine
                to Connector.

    o   INSTALLATION

        o       The standard ISOCOR installation mechanisms will be utilized for
                the initial release. This includes an InstallShield based setup
                program that will install the management console. The management
                console will then be used to install, upgrade and remove
                individual components from the installation CD.

Data Input and Join

    o   REAL-TIME VIEW

        o       Changes to a connected directory will be reflected into the
                MetaView in as timely a fashion as possible. Depending on the
                capabilities of the connected data source for event notification
                this shall be near real-time.

    o   [***]

        o       [***]

    o   SCHEMA/DATA MAPPING AND CONVERSION

        o       The product will provide convenient, user configurable
                mechanisms to map and/or convert schema and/or data between the
                MetaView and connected directories. In particular, this product
                will handle the situation where the [***] for an entry in the
                [***] may be entirely different from the [***] for the
                corresponding entry in the ConnectorView

Performance and Scalability

    o   METAVIEW SIZE

        o       The product shall support multiple [***] in separate [***].

        o       Handle a minimum of [***] entries in a single [***] - note that
                there should be no architectural limitations at [***] entries,
                and that the product will be QA tested with [***].

    o   CONNECTED DIRECTORY SIZE

        o       Subject to the capabilities of the host directory server,
                MetaConnect will handle a minimum of [***] entries to be joined
                into the meta directory MetaView note that there should be no
                architectural limitations at [***] entries within MetaConnect,
                and the product will be QA tested with [***] entries.

    o   ADMINISTRATION PERFORMANCE

        o       Initial import and automatic joining of [***] entries will not
                take more than [***] to complete, unless limited by the
                performance of the connected directory.

Data Management

    o   DATA OWNERSHIP REVERSAL

        o       A configuration option will allow the meta directory to take
                ownership of an attribute previously owned by a foreign
                directory source.

    o   NAMESPACE OWNERSHIP

        o       The meta directory solution will be able to control which
                connected directories can create and delete objects within the
                meta directory.

    o   ATTRIBUTE MANAGEMENT



*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       18
<PAGE>   19

        o       An administrator will be able to configure whether the product
                can create, modify or delete any given attribute of any given
                entry in the MetaView or any connected directory.

    o   SINGLE ADMINISTRATION

        o       The meta directory solution will offer the capability of
                invoking a process or script to create an account in a foreign
                directory based on a given action in the meta directory.

Connector Features

    o   LDAP SUPPORT

        o       Both the Join Engine and some connectors can use LDAP as the
                exclusive means of access to the Connector View, including data
                being synchronized in both directions, as well as change log
                information. The Join Engine also provides plug-in interfaces
                for supporting other data access and change notification
                protocols. These interfaces are used by some connectors,
                including the universal database connector, to provide data
                access to applications that do not provide LDAP support.

    o   CONFIGURATION STORED IN DIRECTORY VIA LDAP

        o       Connectors will store all configuration information, whenever
                feasible, in a directory accessed exclusively via LDAP. Use of
                the NT Registry and other, ad hoc mechanisms for storing and
                updating Connector configuration information will be avoided
                except where these are sound engineering reasons for using them.

    o   CHANGE LOG

        o       Connectors will be able to use a Netscape Directory Server
                change log to become aware of changes to LDAP stored
                configuration information and the connector view.

    o   DIRECTORY SERVER INDEPENDENCE

        o       Connectors will be able to use Netscape Directory Server 3.1,
                without extensions, to store configuration and the connector
                view. It will also be able to use other [***].

    o   REMOTE ADMINISTRATION

        o       The product will enable the administrator to manage connectors
                remotely, over a TCP/IP network.

    o   CONNECTOR IMPLEMENTATION TECHNOLOGY

        o       Some of the exclusive connectors may be implemented using
                variety of technologies including native binaries, scripts
                (including PERL), Universal Database Connector configurations
                and others.




*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       19
<PAGE>   20



                                    EXHIBIT B
                              PAYMENTS AND SUPPORT

1.      PAYMENTS

    1.1  INITIAL LICENSE FEE. Netscape shall pay ISOCOR a non-refundable initial
         source code license fee of [***] for the licenses in the First
         Preliminary Copy within [***] after ISOCOR's delivery of the First
         Preliminary Copy.

    1.2   [***] ROYALTIES.

         a.    Provided that Netscape accepts the Acceptance Candidates pursuant
               to this Agreement, Netscape shall pay ISOCOR non-refundable [***]
               Royalties as listed below in this Section 1.2. [***]

               (i)[***] ROYALTY. The [***] Royalty shall be [***] upon Netscape
                  receipt of the Acceptance Candidates and eventual Acceptance
                  of the Acceptance Candidates. The Second [***] Royalty shall
                  be calculated as the sum of [***] and the following: beginning
                  [***] shall be deducted from [***] until ISOCOR delivers a
                  version of the Acceptance Candidates that Netscape accepts,
                  provided, however, that in no event shall any amounts be
                  deducted from the [***] Amount and provided further, however,
                  that date on which Netscape is deemed to have received the
                  Acceptance Candidate shall be the date the Acceptance
                  Candidate is delivered to Netscape and which Netscape Accepts
                  without having to reject such version and Accept a later
                  re-submission of such Acceptance Candidate. [***]


    1.3  ROYALTY PAYMENTS. Provided Netscape accepts the Acceptance Candidates
         pursuant to the acceptance procedures set forth in Section 2 of Exhibit
         A, Netscape shall pay ISOCOR a royalty ("Royalty") for the applicable
         time period to be calculated as [***], less credits for returns of
         units of the Products or the Royalty Bearing Licensed Programs, for
         each Royalty Bearing Licensed Program distributed by Netscape; provided
         that for Products containing the Licensed Programs which are bundled
         with or are incorporated into other Netscape products, [***] shall be
         the portion of Netscape's net license fees which are attributable to
         such Netscape Product which contains the Licensed Programs. The
         Royalties described in this Section 1.3 shall be subject to the [***]
         Royalty limits described in Section 1.4 of this Exhibit B below.



*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       20
<PAGE>   21

<TABLE>
<CAPTION>
--------------------------------- ------------------------------- -------------------------------
TIME PERIOD                       TECHNOLOGY DISTRIBUTED          % OF NETSCAPE'S ASP DURING
                                                                  APPLICABLE TIME PERIOD TO BE
                                                                  PAID TO ISOCOR
--------------------------------- ------------------------------- -------------------------------

<S>                               <C>                             <C>
From first date after the         ISOCOR Join Engine                          [***]%
Effective Date in which ISOCOR 
makes a new version of the 
Join Engine commercially 
available until the Netscape 
Join Engine Release Date

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

[***] after Netscape Join         Netscape Join Engine                        [***]%
Engine Release Date (beginning
on Netscape Join Engine Release
Date and ending [***]
thereafter)

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

[***] after Netscape Join         Netscape Join Engine                        [***]%
Engine Release Date (beginning
on [***] of the Netscape Join
Engine Release Date and ending
on [***] of the Netscape Join
Engine Release Date)
--------------------------------- ------------------------------- -------------------------------

[***] after Netscape Join         Netscape Join Engine                        [***]
Engine Release Date (beginning
on [***] of the Netscape Join
Engine Release Date and ending
on [***] of the Netscape Join
Engine Release Date)

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

[***] after Netscape Join         Netscape Join Engine                        [***]%
Engine Release Date and
thereafter (beginning on [***]
of the Netscape Join Engine
Release Date)

--------------------------------- ------------------------------- -------------------------------
Term of Agreement                 Standard Connector                          [***]%
--------------------------------- ------------------------------- -------------------------------

Term of Agreement                 Ported Database Connectors                  [***]%
                                  (Oracle, Sybase, SQL or DB2
                                  Database Exclusive Connectors
                                  ported to other platforms
                                  (other than Windows NT) by
                                  Netscape as provided in
                                  Exhibit A, Section 3(E)

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

From Effective Date of            Exclusive Connector                         [***]%
Agreement through the [***] 
after Netscape Join Engine 
Release Date (beginning
on [***] and ending on the 
[***] of the Netscape Join 
Engine Release Date)

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

[***] after Netscape Join         Exclusive Connector                         [***]%
Engine Release Date and 
thereafter (beginning on 
[***] of the Netscape Join
Engine Release Date and ending 
on termination or expiration of
Agreement)

--------------------------------- ------------------------------- -------------------------------
</TABLE>



*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       21
<PAGE>   22

        Any Royalty shall accrue to ISOCOR upon the date Netscape ships any
Licensed Programs or any Products containing the Licensed Programs. All Royalty
fees shall be paid by Netscape [***].

        Within [***], Netscape shall submit to ISOCOR a [***] Statement. Each
such [***] Statement shall be accompanied by payment of Royalty fees, if any are
due, and shall include the following information:

        a)  the number of copies of Royalty Bearing Licensed Programs
            distributed by Netscape;

        b)  the total Royalty fees due ISOCOR for the applicable [***];

        c)  any credits for [***] Royalties applied against Royalty fees due;
            and

        d)  any deduction of the Royalty fees due ISOCOR pursuant to the terms
            of this Agreement.


1.4 MINIMUM/[***] ROYALTIES.

    A.  [***] AFTER NETSCAPE JOIN ENGINE RELEASE DATE. Provided that Netscape
        accepts the Acceptance Candidates pursuant to the terms and conditions
        of this Agreement, for the [***] after the Netscape Join Engine Release
        Date, where "Netscape Join Engine Release Date" is defined as the
        earlier of (i) the date Netscape makes generally available the first
        non-beta or non-alpha version of a Netscape Join Engine released after
        the Effective Date, or (ii) [***], Netscape shall pay ISOCOR minimum
        Royalties (for all Royalty Bearing Licensed Programs) of [***] plus any
        [***] Royalties paid to ISOCOR [***], which shall be made in [***] equal
        installments based on the Netscape Join Engine Release Date, and which
        shall be payable within [***] after the end of the applicable [***]
        period. The [***] installment shall be paid by Netscape within [***] 
        after the Join Engine Release Date. [***]. All minimum Royalties to be 
        paid pursuant to this Section 1.4.a are contingent upon Netscape's
        Acceptance of the Acceptance Candidates.

    B.  [***] AFTER NETSCAPE JOIN ENGINE RELEASE DATE. If Netscape, during the
        [***] after the Netscape Join Engine Release Date, has either: (1)
        licensed at least [***] of the Netscape Join Engine, [***], or (2) [***]
        from all deals in which the Netscape Join Engine is licensed (regardless
        of the number of Netscape Join Engines licensed), [***], then for the
        [***] after the Netscape Join Engine Release Date (beginning on [***] of
        the Netscape Join Engine Release Date and ending on the [***] of the 
        Netscape Join Engine Release Date), Netscape shall pay ISOCOR minimum
        Royalties (for all Royalty Bearing Licensed Programs) of [***] in equal
        [***] installments based on the Join Anniversary Release Date [***]
        beginning on the [***] of the Netscape Join Engine Release Date
        beginning on the [***] of the Netscape Join Engine Release Date), which
        shall be payable within [***] days after the beginning of the applicable
        [***] period (i.e. payments due within [***] after the [***] date of the
        Netscape Join Engine Release Date, and [***] after the beginning of the
        next three [***] thereafter). [***] If Netscape does not license reach
        the minimums described in Section 1.4.b(1) and 1.4.b(2) of this Section
        1.4.b above, then there shall be no minimum Royalty due.




*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       22
<PAGE>   23

2.  SUPPORT

    2.1 ISOCOR SECOND LINE OF SUPPORT.

        A.  SUPPORT FOR OBJECT CODE OF ISOCOR JOIN ENGINE AND ISOCOR MANAGEMENT
            CONSOLE. During the period beginning on the Effective Date and
            ending [***] from the date Netscape first pays ISOCOR minimum
            Royalties (as described in Section 1.4 of this Exhibit B) (the
            "Initial Support Period"), ISOCOR shall provide to Netscape second
            line support services (which is limited to Netscape and not directly
            to Netscape's customers) for ISOCOR's standard products, as
            delivered to Netscape, and relating to the (1) the Object Code of
            the ISOCOR Join Engine and/or (2) the Object Code of the ISOCOR
            Management Center, consistent with the support obligations described
            on Attachment B-1 hereto (which Attachment may be supplemented or
            replaced, from time to time, by mutual agreement), with respect to
            the Licensed Programs listed above and any Products containing the
            Licensed Programs listed above including, without limitation,
            identification of defects in the Connectors (Source Code and Object
            Code) and providing corrections, workarounds and/or patches to
            correct defects or errors in such Licensed Programs (Source Code and
            Object Code). Such Support shall be for ISOCOR's most recent
            versions. [***]

        B.  SUPPORT FOR OBJECT CODE OF TEXT UNIVERSAL CONNECTOR, EXCLUSIVE
            CONNECTORS AND STANDARD CONNECTORS. For the term of this Agreement,
            ISOCOR shall provide to Netscape second line support services (which
            is limited to Netscape and not directly to Netscape's customers) for
            any ISOCOR standard products, as delivered to Netscape, and relating
            to the (1) Object Code of the Exclusive Connectors; (2) the Object
            Code of the Text Universal Connector; and/or (3) the Object Code of
            any Standard Connector, consistent with the support obligations
            described on Attachment B-1 hereto (which Attachment may be
            supplemented or replaced, from time to time, by mutual agreement),
            with respect to the Licensed Programs listed above and any Products
            containing such Licensed Programs including, without limitation,
            identification of defects in the Connectors (Source Code and Object
            Code) and providing corrections, workarounds and/or patches to
            correct defects or errors in such Connectors (Source Code and Object
            Code). Such Support shall be for ISOCOR's most recent versions.
            [***].

    2.2 TECHNICAL SUPPORT OF NETSCAPE FOR SOURCE CODE. During the period
        beginning on the Effective Date and ending [***] after Netscape's
        Acceptance of the Acceptance Candidates pursuant to the acceptance
        procedures set forth in Section 2 of Exhibit A, in addition to the
        back-end support services described above, ISOCOR shall provide to
        Netscape, for up to[***], for any Source Code provided hereunder, the
        following technical support services:

        A.  ISOCOR shall appoint a technical contact to which Netscape may
            address all technical questions relating to ISOCOR technologies.
            Upon execution of this Agreement, the parties shall determine a
            mutually agreeable procedure by which Netscape shall direct its
            technical questions to the appropriate ISOCOR technical contact.

        B.  ISOCOR shall promptly answer all technical questions asked by
            Netscape relative to the Licensed Programs.




*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       23
<PAGE>   24



        2.3 TRAINING OF NETSCAPE. ISOCOR shall conduct, without cost to
            Netscape, and at such times as Netscape shall designate, [***]
            technical training session with a mutually agreeable date and
            agenda. All such training shall occur at Netscape's Mountain View,
            CA facilities, and shall include a walk through of the Source Code
            to the Licensed Programs delivered to Netscape. Netscape shall not
            be limited in the number of attendees that may be present at any
            such training session and will provide sufficient facilities and
            equipment to conduct such training.

        2.4 UPGRADES, UPDATES, PORTS, ERROR CORRECTIONS AND ENHANCEMENTS.

            A.  OBJECT CODE. With respect to the Licensed Programs to which
                Netscape has only Object Code rights, ISOCOR will include
                Netscape in its alpha and beta programs for any upgrades or
                updates to the Licensed Programs released during the term of
                this Agreement, and will provide Netscape with the production
                version of such upgrades and/or updates of the Licensed Programs
                simultaneously with its earliest release of such upgrades and/or
                updates to other customers. ISOCOR shall also provide Netscape
                during the term hereof with any error corrections, bug fixes and
                enhancements to the Licensed Programs simultaneously with its
                earliest release of such error corrections, bug fixes or
                enhancements to other customers. [***].

            B.  SOURCE CODE. With respect to the Licensed Programs to which
                Netscape has Source Code rights, for the period beginning on
                Netscape's receipt of the Acceptance Candidates and ending [***]
                after Netscape's Acceptance of the Acceptance Candidates
                pursuant to the acceptance procedures set forth in Section 2 of
                Exhibit A, ISOCOR will provide Netscape with any error
                corrections and bug fixes to the Licensed Programs (Source Code)
                simultaneously with its earliest release of such error
                corrections or bug fixes to other customers. [***].

        2.5 SUPPORT FEES. During any period in which Netscape is receiving
            support from Isocor, Netscape shall pay to ISOCOR a support fee of
            [***] for Connectors in the previous Netscape [***].




*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       24
<PAGE>   25



                                 ATTACHMENT B-1
                               SUPPORT OBLIGATIONS

ISOCOR shall provide to Netscape support services consistent with the following
support obligations:

1.  DEFINITIONS

        1.1 "ERROR" means any instance where a product or update or upgrade to a
product does not substantially conform to its documented features and
specifications.

        1.2 "WORKAROUND" means a method by which a user of a product can, by
making a limited number of procedural or programming changes in a product,
prevent the occurrence or re-occurrence of an Error. Programming changes include
adjustments to set-up and configurations files or other settings that do not
require recompilation.

        1.3 "RESPOND" means and includes: taking and logging the Error call; in
the case of Priority 1 Errors, providing to Netscape an action/resolution plan
within four (4) hours of initial call receipt and acknowledgment; and, in cases
of Priority 1 and 2 Errors, making best efforts on a continuing basis to cure
the Error until the Error is cured.

2.  OBLIGATIONS

        2.1 ERROR REPORTING. Errors may be reported on a 24 hours per day, 365
day per year basis for priority 1 and priority 2 errors. Other errors may be
reported during normal business hours. During normal business hours, ISOCOR's
technical staff shall be available to receive error reports directly from
Netscape by telephone. Outside of normal business hours, Netscape may report
errors by pager, electronic mail, voice mail, fax or telephonic recording
capability. ISOCOR shall provide Netscape with a pager number for both a primary
and secondary pager which will be carried by appropriate ISOCOR support
personnel at all times and which Netscape may use to report priority 1 and
priority 2 errors at any time.

        2.2 SUPPORT REQUESTS. ISOCOR will Respond and use best efforts to
correct or provide a Workaround to Priority 1 and Priority 2 Errors that
Netscape identifies, classifies and reports; and will use reasonable commercial
efforts to Respond to other Errors within the time frames set forth below.
<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------
                                                                         STATUS UPDATES (PROVIDED
PRIORITY              FAILURE DESCRIPTION            INITIAL RESPONSE    UPON CUSTOMER'S REQUEST
                                                           TIME          AFTER NETSCAPE'S INITIAL
                                                                         RESPONSE)

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

<S>      <C>                                         <C>                 <C>                   
    1    Enterprise-critical (Product is not              1 hour            By customer agreement
         functioning)

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

    2    Severe Impact - Product inconsistency which      2 business        Once per business day 
         significantly decreases Customer productivity    hours
         (periodic work stoppages, feature crashes)

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

    3    Degraded Operations: Product inconsistency       4 business        Once every 3 business
         which slightly impairs customer productivity     hours             days
         (Customer can work around problem)

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

    4    Minimal Impact: desired change in Product        next business     Release notes or plan
         (documentation update, cosmetic defects,         day               for next release
         enhancement requests)

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

</TABLE>

                                       25
<PAGE>   26



                                    EXHIBIT C
                              EXCLUSIVE CONNECTORS

 [***]

 [***]

 [***]



*   Confidential treatment requested pursuant to a request for confidential
    treatment filed with the Securities and Exchange Commission. Omitted
    portions have been filed separately with the Commission.


                                       26
<PAGE>   27



                                    EXHIBIT D
                                    MARKETING

1. DEVELOPMENT EFFORTS. Netscape and ISOCOR shall, in good faith, use
commercially reasonable efforts to coordinate their development efforts such
that the Netscape and ISOCOR versions of the Join Engine and/or Connector(s)
remain compatible.

2. PRICE LISTS. Netscape and ISOCOR shall make available to each other each
party's published price list simultaneously with such price list's availability
to each party's business customers.

3. PRESS RELEASE. Netscape and Participant shall issue a press release
announcing that Netscape is planning to ship the Licensed Programs with the
Products; the content and timing of such press release will be subject to both
parties' prior review and approval.



                                       27


<PAGE>   28



                                    EXHIBIT E
                          Documentation and Test Cases
                           To be Delivered to Netscape


1. Specifications for configuration schema

2. Design documentation associated with the delivered source code

3. Build instructions and a description of the build environment (OS release,
compiler release, etc...)

4. Release notes for the ISOCOR v1.1 binary release, including information about
execution environment, installation procedures, and known bugs.

5. User and administrator manuals for the Second Preliminary Copy binary
release. These will be provided initially in FrameMaker format, complete with
cross references. In addition, 10 printed copies will be provided.

6. Complete help text associated with the Management Console in machine readable
form.

7. A summary of the available test cases and test results which are sufficiently
detailed that Netscape engineers can verify the results. These test cases will
include a representative set of feature tests, as well as some stress, capacity,
and boundary tests. These tests should all be run using Netscape Directory
Server (R3.1 or later) for all LDAP directory storage.



                                       28
<PAGE>   29



                                    EXHIBIT F
                    MINIMUM TEST CRITERIA FOR ACCEPTANCE TEST

1.  Using the Binaries, the Release Notes, and other ISOCOR Documentation,
    Netscape engineers are able to successfully install and run the binary
    release (in the target environments specified by ISOCOR).

2.  The User Documentation for the binary release will generally match the
    functionality of the binaries. For example, the Connector documentation
    matches the LDAP version of the Connectors.

3.  Netscape engineers are able to build working binaries from the unmodified
    Source Code and Build Scripts (for ISOCOR's target environments).

4.  The Design Docs are generally consistent with the Source Code delivered.

5.  The exhibited Functionality of the ISOCOR product does not omit significant
    features in the "Technical Specifications" included as a part of the Source
    License Agreement.

6.  All major functionality of the ISOCOR product (including Join Engine, and
    Connectors works correctly using the binaries built from unmodified source
    by Netscape. For example, incremental updates, multi-threading in both the
    Join Engine and Connectors, automatic joins for a variety of Connector View
    schema's, and manual joins for a variety of Connector View schema's all
    work. This is equivalent to saying that there are no P1 or P2 bugs known to
    ISOCOR or detected by Netscape during its assessment of functionality which
    are not corrected during the acceptance test..

7.  Test programs are buildable and runable by Netscape engineers.

8.  Available reported test results which are verifiable by Netscape engineers
    on binaries built from unmodified source at Netscape, with minor exceptions.


                                       29