Document:

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                                                                     Exhibit 4.2

                               FIRST AMENDMENT TO
                          FOURTH AMENDED AND RESTATED
                          INVESTORS' RIGHTS  AGREEMENT

          Pursuant to Section 3.8 of the Fourth Amended and Restated Investors'
Rights Agreement dated as of August 13, 1999 (the "Agreement"), between Kana
Communications, Inc., a Delaware corporation, (the "Company") and the various
other parties thereto, the Company and the holders of a majority of the
Registrable Securities (as defined in the Agreement) hereby amend the Agreement
as of                 , 2000, as provided below.

          1.  Registration Rights.  Section 1.1(g) of the Agreement shall be
              -------------------
amended in its entirety to read as follows:

                (g)  "Registrable Securities" means (i) Common Stock issuable
          or issued upon conversion of the Series A Preferred Stock, Series A1
          Preferred Stock, Series B Preferred Stock, Series B1 Preferred Stock,
          Series C Preferred Stock, Series C1 Preferred Stock, Series D
          Preferred Stock and Series D1 Preferred Stock, (ii) Common Stock
          issued to Mark Gainey and Michael Horvath (for purposes only of
          Sections 1.3, 1.7, 1.8, 1.10 and 3.8 of this Agreement), (iii) the
          Common Stock issuable or issued upon conversion of the Series A
          Preferred Stock (including the Series A1 Preferred Stock) issued upon
          exercise of two warrants held by Ragnild Horvath and the Beni M.
          Horvath Trust 1991, (iv) all shares held by the parties listed on
          Schedule B hereto acquired or to be acquired in connection with the
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          Company's acquisition of Connectify pursuant to the Plan of
          Reorganization, (v) all shares held by the parties listed on Schedule
                                                                       --------
          C hereto acquired or to be acquired in connection with the Company's
          -
          acquisition of Silknet Software Inc. ("Silknet") pursuant to an
          Agreement and Plan of Reorganization dated as of February 6, 2000
          between Silknet, the Company and Pistol Acquisition Corp., a wholly-
          owned subsidiary of the Company, and (vi) any Common Stock of the
          Company issued as (or issuable upon the conversion or exercise of any
          warrant, right or other security which is issued as ) a dividend or
          other distribution with respect to, or in exchange for or in
          replacement of the shares referenced in (i), (ii), (iii), (iv) and (v)
          above, excluding in all cases, however, any Registrable Securities
          sold by a person in a transaction in which such person's rights under
          this Section 1 are not assigned.

In addition, the preamble to the Agreement shall be amended in its entirety to
read as follows:

                THIS FOURTH AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT
          is made as of the 13th day of August 1999, by and among Kana
          Communications, Inc. a Delaware corporation, (the "Company"), the
          parties listed on Schedule A hereto (the "Existing Investors") and
                            ----------
          the parties listed on Schedule B (the "Connectify Stockholders") and
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          Schedule C hereto (collectively with the Existing Investors and the
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          Connectify Stockholders, the "Investors").

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          2.  Schedule C.  The Agreement is hereby amended such that Schedule A
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to this First Amendment to Fourth Investors' Rights Agreement is added to and
made a part of the Agreement as Schedule C to the Agreement.

          3.  Notwithstanding Sections 1 and 2 above, each person listed on
Schedule A hereto shall not be considered an Investor and shall not have any
rights, benefits or obligations under the Agreement, as amended, unless such
person has executed and delivered this First Amendment.  In addition, each
person listed on Schedule A hereto, upon executing and delivering this First
Amendment agrees to be bound by the terms, conditions, limitations and rights
imposed or granted by the Agreement.

          IN WITNESS WHEREOF, the parties have executed this First Amendment to
Fourth Investors' Rights Agreement as of the date first above written.

                                KANA COMMUNICATIONS, INC.

                                By_________________________________________
                                Name:
                                Title:

                                MARK S. GAINEY

                                ___________________________________________

                                [Signature page of First Amendment to Fourth
                                 Amended and Restated Investors' Rights
                                 Agreement]

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                                DRAPER FISHER ASSOCIATES FUND IV, L.P.

                                ___________________________________________
                                Name:
                                Title:

                                DRAPER FISHER PARTNERS IV, LLC

                                ___________________________________________
                                Name:
                                Title:

                    [Signature page of First Amendment to
          Fourth Amended and Restated Investors' Rights Agreement]

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                                BENCHMARK CAPITAL PARTNERS, L.P.
                                By:  Benchmark Capital Management Co., L.L.C.,
                                     its General Partner

                                ___________________________________________
                                Name:
                                Title:

                                BENCHMARK FOUNDERS' FUND, L.P.
                                By:  Benchmark Capital Management Co., L.L.C.,
                                     its General Partner

                                ___________________________________________
                                Name:
                                Title:

                    [Signature page of First Amendment to
          Fourth Amended and Restated Investors' Rights Agreement]

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<PAGE>

[Signature Page for new Investors]

                    [Signature page of First Amendment to
          Fourth Amended and Restated Investors' Rights Agreement]

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<PAGE>

                                   Schedule A
                                   ----------

                                       6THE SECURITIES  REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933,  AS AMENDED (THE "ACT").  THESE  SECURITIES  HAVE BEEN ACQUIRED FOR
INVESTMENT,  AND NOT WITH A VIEW TO DISTRIBUTION OR RESALE, AND MAY NOT BE SOLD,
PLEDGED,  MORTGAGED,  HYPOTHECATED  OR  OTHERWISE  TRANSFERRED  (1)  WITHOUT  AN
EFFECTIVE  REGISTRATION STATEMENT UNDER THE ACT COVERING THESE SECURITIES OR (2)
UNLESS AN EXEMPTION FROM REGISTRATION IS AVAILABLE.

                           SHANDON SCIENTIFIC LIMITED
                        Promissory Note Due July 15, 2001
                        Runcorn, Cheshire, United Kingdom

                                                             As of July 15, 1999

         For value received, Shandon Scientific Limited, a corporation organized
under the laws of England and Wales (the  "Company"),  hereby promises to pay to
Life Sciences International Limited (hereinafter referred to as the "Payee"), or
its registered  assigns, on July 15, 2001, as described below, the principal sum
of ten million one hundred thousand GBP ((pound)10,100,000) or such part thereof
as then remains unpaid, to pay interest from the date hereof on the whole amount
of said  principal  sum  remaining  from time to time unpaid at a rate per annum
equal to 6.05%, such interest is payable in arrears on the first business day of
each fiscal quarter of the Company,  until all amounts  outstanding  are paid in
full.  Overdue  principal  and interest  shall bear interest at a rate per annum
equal to the rate of interest announced from time to time by BankBoston, N.A. at
its head  office in Boston,  Massachusetts  as its "base  rate" plus one percent
(1%).  Principal and all accrued but unpaid interest shall be repaid on July 15,
2001.  Principal  and interest  shall be payable in lawful money of England,  in
immediately  available  funds,  at the principal  office of the Payee or at such
other place as the legal  holder may  designate  from time to time in writing to
the Company. Interest shall be computed on an actual 360-day basis.

         This Note may be prepaid at any time or from time to time,  in whole or
in part, without any premium or penalty.  All prepayments shall be applied first
to accrued interest and then to principal.

         The then unpaid principal amount of, and interest  outstanding on, this
Note shall be and become  immediately  due and payable without notice or demand,
at the option of the holder hereof,  upon the occurrence of any of the following
events:

                  (a) the failure of the Company to pay any amount due hereunder
         within ten (10) days of the date when due;

                  (b)  any   representation,   warranty  or  statement  made  or
         furnished to the Payee by the Company in  connection  with this Note or
         the transaction  from which it arises shall prove to have been false or
         misleading  in  any  material  respect  as of the  date  when  made  or
         furnished;

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                  (c) the failure of the Company to pay its debts as they become
         due,  the  insolvency  of the  Company,  the filing by or  against  the
         Company of any petition under the insolvency laws of any  jurisdiction,
         or the making by the Company of an assignment or trust mortgage for the
         benefit of creditors  or the  appointment  of a receiver,  custodian or
         similar  agent with  respect  to, or the  taking by any such  person of
         possession of, any property of the Company;

                  (d) the sale by the Company of all or substantially all of its
         assets;

                  (e) the merger or  consolidation  of the Company  with or into
         any other  corporation in a transaction in which the Company is not the
         surviving entity;

                  (f) the issuance of any writ of attachment, by trustee process
         or  otherwise,  or any  restraining  order or  injunction  not removed,
         repealed or dismissed  within thirty (30) days of issuance,  against or
         affecting  the person or property of the  Company or any  liability  or
         obligation of the Company to the holder hereof; and

                  (g) the suspension of the transaction of the usual business of
         the Company.

         Upon surrender of this Note for transfer or exchange, a new Note or new
Notes of the same tenor  dated the date to which  interest  has been paid on the
surrendered  Note and in an  aggregate  principal  amount  equal  to the  unpaid
principal amount of the Note so surrendered will be issued to, and registered in
the name of, the transferee or transferees.  The Company may treat the person in
whose  name this Note is  registered  as the owner  hereof  for the  purpose  of
receiving payment and for all other purposes.

         In case any payment herein provided for shall not be paid when due, the
Company further promises to pay all cost of collection, including all reasonable
attorneys' fees.

         No delay or omission on the part of the Payee in  exercising  any right
hereunder  shall  operate as a waiver of such right or of any other right of the
Payee,  nor shall any delay,  omission or waiver on any one occasion be deemed a
bar to or waiver  of the same or any other  right on any  future  occasion.  The
Company hereby waives presentment, demand, notice of prepayment, protest and all
other  demands  and  notices  in  connection  with  the  delivery,   acceptance,
performance, default or enforcement of this Note. The undersigned hereby assents
to any  indulgence  and any  extension  of time for payment of any  indebtedness
evidenced hereby granted or permitted by the Payee.

         This Note shall be governed by and  construed in accordance  with,  the
laws of England.

Executed and delivered as a deed                            )
By SHANDON SCIENTIFIC LIMITED               Colin Maddix    )  /s/ Colin Maddix
Acting by one director and a second                         )  -----------------
director or the company secretary           Damian Hickey   )  /s/ Damian Hickey
                                                               -----------------

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