<PAGE>

                                                                     EXHIBIT 4.2
                                                                     -----------


          This Warrant and any shares acquired upon the exercise of this Warrant
          have not been registered under the Securities Act of 1933, as amended,
          and may not be transferred, sold or otherwise disposed of except while
          such a registration is in effect or pursuant to an exemption from
          registration under said Act.

          The holder of this Warrant is subject to certain obligations contained
          in a Standstill Agreement dated as of August 29, 2000, as amended, a
          copy of which is available for inspection at the principal office of
          the issuer hereof, and will be furnished without charge to the holder
          of this Warrant upon written request.


                            ENTERASYS NETWORKS, INC.

                                    Warrant

                                                        Rochester, New Hampshire
No.   W-__________                                               August __, 2001


          ENTERASYS NETWORKS, INC., a Delaware corporation, formerly known as
Cabletron Systems, Inc. (the "Company"), for value received, hereby certifies
that [Name of Investor], or registered assigns, is entitled to purchase from the
Company up to [_______] duly authorized, validly issued, fully paid and
nonassessable shares of Common Stock, par value $.01 per share (the "Common
Stock"), of the Company at the initial purchase price per share of  $6.20 (the
"Initial Warrant Price"), at any time or from time to time, prior to 5:00 P.M.
Rochester, New Hampshire time, on August 29, 2004 (the "Expiration Date"), all
subject to the terms, conditions and adjustments set forth below in this
Warrant.

          This Warrant is one of the Replacement Warrants (the "Warrants," such
term to include any warrants issued in substitution therefor) issued pursuant to
the Amended and Restated Securities Purchase Agreement dated as of August 29,
2000 (as from time to time in effect, the "Purchase Agreement") among the
Company and the investors named therein (the "Investors").  The Warrants so
issued evidence rights to purchase an aggregate of 7,400,000 shares of Common
Stock, subject to adjustment as provided herein.  Certain capitalized terms used
in this Warrant are defined in Section 11 hereof.
<PAGE>

1.  EXERCISE OR CONVERSION OF WARRANT.

     1.1.  Manner of Exercise or Conversion; Payment.

     1.1.1.  Exercise.  This Warrant may be exercised by the holder hereof, in
whole or in part, during normal business hours on any Business Day on or prior
to the Expiration Date, by surrender of this Warrant to the Company at its
office maintained pursuant to Section 10.2(a) hereof, accompanied by a
subscription in substantially the form attached to this Warrant (or a reasonable
facsimile thereof) duly executed by such holder and accompanied by payment, in
cash, by certified check payable to the order of the Company or by wire transfer
(or by any combination of such methods), in the amount obtained by multiplying
(a) the number of shares of Common Stock (without giving effect to any
adjustment thereof) designated in such subscription by (b) the Initial Warrant
Price, and such holder shall thereupon be entitled to receive the number of duly
authorized, validly issued, fully paid and nonassessable shares of Common Stock
(or Other Securities) determined as provided in Sections 2 and 3 hereof.

     1.1.2.  Conversion.  This Warrant may be converted by the holder hereof, in
whole or in part, into shares of Common Stock, during normal business hours on
any Business Day on or prior to the Expiration Date, by surrender of this
Warrant to the Company at its office maintained pursuant to Section 10.2(a)
hereof, accompanied by a conversion notice in substantially the form attached to
this Warrant (or a reasonable facsimile thereof) duly executed by such holder,
and such holder shall thereupon be entitled to receive a number of duly
authorized, validly issued, fully paid and nonassessable shares of Common Stock
(or Other Securities) equal to:

             (i)  an amount equal to:

                  (a)  an amount equal to (x) the number of shares of Common
                       Stock (or Other Securities) determined as provided in
                       Sections 2 and 3 hereof which such holder would be
                       entitled to receive upon exercise of this Warrant for the
                       number of shares of Common Stock designated in such
                       conversion notice multiplied by (y) the Current Market
                       Price (or, if such shares are converted in connection
                       with a Company Sale (as defined in the Purchase
                       Agreement), the Market Price) on the date of conversion
                       of each such share of Common Stock (or such Other
                       Securities) so receivable upon such exercise

                       minus

                                      -2-
<PAGE>

               (b)  an amount equal to (x) the number of shares of Common Stock
                    (without giving effect to any adjustment thereof) designated
                    in such conversion notice multiplied by (y) the Initial
                    Warrant Price

               divided by

         (ii)  such Current Market Price (or, if such shares are converted in
               connection with a Company Sale (as defined in the Purchase
               Agreement), the Market Price) of each such share of Common Stock
               (or Other Securities).

For all purposes of this Warrant (other than this Section 1.1), any reference
herein to the exercise of this Warrant shall be deemed to include a reference to
the conversion of this Warrant into Common Stock (or other Securities) in
accordance with the terms of this Section 1.1.2.

     1.2.  When Exercise Effective.  Each exercise of this Warrant shall be
deemed to have been effected immediately prior to the close of business on the
Business Day on which this Warrant shall have been surrendered to the Company as
provided in Section 1.1 hereof, and at such time the Person or Persons in whose
name or names any certificate or certificates for shares of Common Stock (or
Other Securities) shall be issuable upon such exercise as provided in Section
1.3 hereof shall be deemed to have become the holder or holders of record
thereof.

     1.3.  Delivery of Stock Certificates, etc. Promptly after each exercise of
this Warrant, in whole or in part, and in any event within five Business Days
thereafter, the Company at its expense (including the payment by it of any
applicable issue taxes) will cause to be issued in the name of and delivered to
the holder hereof or, subject to Section 8 hereof, as such holder (upon payment
by such holder of any applicable transfer taxes) may direct:

               (a)  a certificate or certificates for the number of duly
     authorized, validly issued, fully paid and nonassessable shares of Common
     Stock (or Other Securities) to which such holder shall be entitled upon
     such exercise plus, in lieu of any fractional share to which such holder
     would otherwise be entitled, cash in an amount equal to the same fraction
     of the Market Price per share on the Business Day next preceding the date
     of such exercise; and

               (b)  in case such exercise is in part only, a new Warrant or
     Warrants of like tenor, dated the date hereof and calling in the aggregate
     on the face or faces thereof for the number of shares of Common Stock equal
     (without giving effect to any adjustment thereof) to the number of such
     shares called for on the face of this Warrant minus the

                                      -3-
<PAGE>

     number of such shares designated by the holder upon such exercise as
     provided in Section 1.1 hereof.

2.  ADJUSTMENT OF COMMON STOCK ISSUABLE UPON EXERCISE.

     2.1.  General; Number of Shares; Warrant Price.  The number of shares of
Common Stock which the holder of this Warrant shall be entitled to receive upon
each exercise hereof shall be determined by multiplying the number of shares of
Common Stock which would otherwise (but for the provisions of this Section 2) be
issuable upon such exercise, as designated by the holder hereof pursuant to
Section 1.1 hereof, by the fraction of which (a) the numerator is the Initial
Warrant Price and (b) the denominator is the Warrant Price in effect on the date
of such exercise.  The "Warrant Price" shall initially be the Initial Warrant
Price, shall be adjusted and readjusted from time to time as provided in this
Section 2 and, as so adjusted or readjusted, shall remain in effect until a
further adjustment or readjustment thereof is required by this Section 2.

     2.2.  Dividends and Distributions.  In case the Company at any time or from
time to time after the date hereof shall declare, order, pay or make a dividend
or other distribution (including without limitation any distribution of cash,
stock or other securities or property, by way of dividend or spin-off,
reclassification, recapitalization or similar corporate rearrangement or
otherwise) on the Common Stock, other than a dividend payable in shares of
Common Stock, then, and in each such case, the Warrant Price shall be reduced,
effective as of immediately after the close of business on the record date fixed
for the determination of holders of any class of securities entitled to receive
such dividend or distribution, to a price (calculated to the nearest .001 of a
cent) determined by multiplying the Warrant Price in effect immediately prior to
the close of business on such record date by a fraction:

     (x)    the numerator of which shall be the Current Market Price in effect
            on such record date or, if the Common Stock trades on an ex-dividend
            basis, on the date prior to the commencement of ex-dividend trading,
            less the amount of such dividend or distribution (as determined by
            the Board of Directors of the Company) applicable to one share of
            Common Stock; and

     (y)    the denominator of which shall be such Current Market Price.

Notwithstanding the foregoing provisions of this Section 2.2, no adjustment to
the Warrant Price shall take place pursuant to this Section 2.2 in respect of
(i) any dividend or distribution by the Company of shares of capital stock of an
Operating Subsidiary in any Spin-Off, (ii) any payment by the Company of
quarterly or other regularly scheduled cash dividends, (iii) any purchase or
repurchase by the Company of any shares of Common Stock or (iv) any dividend

                                      -4-
<PAGE>

or distribution referred to in this Section 2.3 if such dividend or distribution
is not actually paid or made (whether or not a record date therefor shall have
been declared).

     2.3.  Treatment of Stock Dividends, Stock Splits, etc. In case the Company
at any time or from time to time after the date hereof shall declare or pay any
dividend or other distribution on the Common Stock payable in shares of Common
Stock, or shall effect a subdivision of the outstanding shares of Common Stock
into a greater number of shares of Common Stock (by reclassification or
otherwise than by payment of a dividend in shares of Common Stock), then, and in
each such case, additional shares of Common Stock shall be deemed to have been
issued (a) in the case of any such dividend or other distribution, immediately
after the close of business on the record date for the determination of holders
of any class of securities entitled to receive such dividend, or (b) in the case
of any such subdivision, immediately after the close of business on the day
immediately prior to the day upon which such corporate action becomes effective.
Effective at the time such additional shares of Common Stock shall be deemed to
have been issued, the Warrant Price shall be reduced to a price (calculated to
the nearest .001 of a cent) determined by multiplying the Warrant Price in
effect immediately prior to such time by a fraction:

     (x)   the numerator of which shall be the number of shares of Common Stock
           outstanding immediately prior to such time; and

     (y)   the denominator of which shall be the number of shares of Common
           Stock outstanding at such time (including the shares of Common Stock
           deemed to have been issued at such time in respect of any such
           dividend or subdivision).

Notwithstanding the foregoing provisions of this Section 2.3, no adjustment of
the Warrant Price shall take place in respect of any dividend or distribution
referred to in this Section 2.3 if such dividend is not actually paid (whether
or not a record date therefor shall have been declared).

     2.4.  Adjustments for Combinations, etc.  In case the outstanding shares of
Common Stock shall be combined or consolidated, by reclassification or
otherwise, into a lesser number of shares of Common Stock, then, and in each
such case, the Warrant Price shall be increased, concurrently with the
effectiveness of such combination or consolidation, to a price, calculated to
the nearest .001 of a cent, determined by multiplying the Warrant Price in
effect immediately prior to such combination or consolidation by a fraction:

     (x)   the numerator of which shall be the number of shares of Common Stock
           outstanding immediately prior to the effectiveness of such
           combination or consolidation; and

                                      -5-
<PAGE>

     (y)   the denominator of which shall be the number of shares of Common
           Stock outstanding at the time of such effectiveness after giving
           effect to such combination or consolidation.

     2.5.  Adjustment for Spin-Offs.  As of the close of business on the first
trading day following the Company's distribution to holders of Common Stock (or
Other Securities) of the capital stock of an Operating Subsidiary in any Spin-
Off (the "Applicable Distribution Date"), the Warrant Price shall be reduced to
a price (calculated to the nearest .001 of a cent) determined by multiplying the
Warrant Price in effect immediately prior to such adjustment by a fraction:

     (x)   the numerator of which is the Post-Spin-Off Warrant Value as of the
           close of business on such trading day; and

     (y)   the denominator of which is the sum of (A) the Post-Spin-Off Warrant
           Value as of the close of business on such trading day, plus (B) the
                                                                  ----
           Subsidiary Warrant Value as of the close of business on such trading
           day.


3.  CONSOLIDATION, MERGER, ETC.

     3.1.  Adjustments for Consolidation, Merger, Sale of Assets,
Reorganization, etc. In case the Company after the date hereof (a) shall
consolidate with or merge into any other Person and shall not be the continuing
or surviving corporation of such consolidation or merger, or (b) shall permit
any other Person to consolidate with or merge into the Company and the Company
shall be the continuing or surviving Person but, in connection with such
consolidation or merger, the Common Stock or Other Securities shall be changed
into or exchanged for stock or other securities of any other Person or cash or
any other property, or (c) shall transfer all or substantially all of its
properties or assets to any other Person, or (d) shall effect a capital
reorganization or reclassification of the Common Stock or Other Securities
(other than a capital reorganization or reclassification to the extent that such
capital reorganization or reclassification results in the issue of additional
shares of Common Stock for which adjustment in the Warrant Price is provided in
Section 2 hereof), then, and in the case of each such transaction, proper
provision shall be made so that, upon the basis and the terms and in the manner
provided in this Warrant, the holder of this Warrant, upon the exercise hereof
at any time after the consummation of such transaction, shall be entitled to
receive (at the aggregate Warrant Price in effect at the time of such
consummation for all Common Stock or Other Securities issuable upon such
exercise immediately prior to such consummation), in lieu of the Common Stock or
Other Securities issuable upon such exercise prior to such consummation, the
greatest amount of securities, cash or other property to which such holder would
actually ha ve been entitled as a shareholder upon such consummation if such
holder had

                                      -6-
<PAGE>

exercised the rights represented by this Warrant immediately prior thereto
(assuming such shareholder failed to exercise any rights of election and
received per share the kind and amount of consideration receivable per share by
a plurality of the non-electing shares), subject to adjustments (subsequent to
such consummation) as nearly equivalent as possible to the adjustments provided
for in Sections 2 and 3 hereof.

     3.2.  Assumption of Obligations. Notwithstanding anything contained in this
Warrant to the contrary, the Company will not effect any of the transactions
described in clauses (a) through (d) of Section 3.1 hereof unless, prior to the
consummation thereof, each person (other than the Company) which may be required
to deliver any stock, securities, cash or property upon the exercise of this
Warrant as provided herein shall assume, by written instrument delivered to the
holder of this Warrant, (a) the obligations of the Company under this Warrant
(and if the Company shall survive the consummation of such transaction, such
assumption shall be in addition to, and shall not release the Company from, any
continuing obligations of the Company under this Warrant), and (b) the
obligation to deliver to such holder such shares of stock, securities, cash or
property as, in accordance with the foregoing provisions of this Section 3, such
holder may be entitled to receive.

4.  NO DILUTION OR IMPAIRMENT.  The Company will not, by amendment of its
certificate of incorporation or through any consolidation, merger,
reorganization, transfer of assets, dissolution, issue or sale of securities or
any other voluntary action, take any action to avoid or to seek to avoid the
observance or performance of any of the terms of this Warrant, but will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such action as may be necessary or appropriate in order to protect
the rights of the holder of this Warrant specifically provided herein.  Without
limiting the generality of the foregoing, the Company (a) will not permit the
par value of any shares of stock receivable upon the exercise of this Warrant to
exceed the amount payable therefor upon such exercise, (b) will take all such
action as may be necessary or appropriate in order that the Company may validly
and legally issue fully paid and nonassessable shares of stock on the exercise
of the Warrants from time to time outstanding, and (c) will not take any action
which results in any adjustment of the Warrant Price if the total number of
shares of Common Stock (or Other Securities) issuable after the action upon the
exercise of all of the Warrants would exceed the total number of shares of
Common Stock (or Other Securities) then authorized by the Company's certificate
of incorporation and available for the purpose of issue upon such exercise.

5.  REPORT AS TO ADJUSTMENTS.  In each case of any adjustment or readjustment in
the shares of Common Stock (or Other Securities) issuable upon the exercise of
this Warrant, the Company will promptly compute such adjustment or readjustment
in accordance with the terms of this Warrant and prepare a report setting forth
such adjustment or readjustment and showing in reasonable detail the method of
calculation thereof and the facts upon which such adjustment or readjustment is
based, including a statement of the Warrant Price in effect immediately prior

                                      -7-
<PAGE>

to and after giving effect to such adjustment or readjustment. The Company will
forthwith mail a copy of each such report to each holder of a Warrant and will,
upon the written request at any time of any holder of a Warrant, furnish to such
holder a like report setting forth the Warrant Price at the time in effect and
showing in reasonable detail how it was calculated. The Company will also keep
copies of all such reports at its office maintained pursuant to Section 10.2(a)
hereof and will cause the same to be available for inspection at such office
during normal business hours by any holder of a Warrant or any prospective
purchaser of a Warrant designated by the holder thereof.

6.  NOTICES OF CORPORATE ACTION.  In the event of

           (a)  any taking by the Company of a record of the holders of any
      class of securities for the purpose of determining the holders thereof who
      are entitled to receive any dividend or other distribution, or any right
      to subscribe for, purchase or otherwise acquire any shares of stock of any
      class or any other securities or property, or to receive any other right,
      or

           (b)  any capital reorganization of the Company, any reclassification
      or recapitalization of the capital stock of the Company or any
      consolidation or merger involving the Company and any other Person or any
      transfer of all or substantially all the assets of the Company to any
      other Person, or

           (c)  any voluntary or involuntary dissolution, liquidation or
                winding-up of the Company,

the Company will mail to each holder of a Warrant a notice specifying (i) the
date or expected date on which any such record is to be taken for the purpose of
such dividend, distribution or right, and the amount and character of such
dividend, distribution or right, and (ii) the date or expected date on which any
such reorganization, reclassification, recapitalization, consolidation, merger,
transfer, dissolution, liquidation or winding-up is to take place, and the time,
if any such time is to be fixed, as of which the holders of record of Common
Stock (or Other Securities) shall be entitled to exchange their shares of Common
Stock (or Other Securities) for the securities or other property deliverable
upon such reorganization, reclassification, recapitalization, consolidation,
merger, transfer, dissolution, liquidation or winding-up.

7.  LISTING OF COMMON STOCK.  At any time Common Stock is listed or admitted to
trading (as applicable) on any national securities exchange or designated as a
National Market System security by the NASD, the Company will, at its expense,
obtain promptly and maintain the approval for listing and admission to trading
(as applicable) on each such exchange and system, upon official notice of
issuance, the shares of Common Stock issuable upon exercise of

                                      -8-
<PAGE>

the then outstanding Warrants and maintain the listing or trading (as
applicable) of such shares after their issuance.

8.  RESTRICTIONS ON TRANSFER.  Each certificate for Common Stock (or Other
Securities) issued upon the exercise of any Warrant, each certificate issued
upon the direct or indirect transfer of any such Common Stock (or Other
Securities), all Warrants issued pursuant to the Purchase Agreement and each
Warrant issued upon direct or indirect transfer or in substitution for any
Warrant pursuant to Section 10 hereof shall be transferable only upon
satisfaction of the conditions specified in Section 4.01 of the Standstill
Agreement and in this Section 8 and shall be stamped or otherwise imprinted with
legends in substantially the form required by Section 4.02 of the Standstill
Agreement.

9.  RESERVATION OF STOCK, ETC.  The Company will at all times reserve and keep
available, solely for issuance and delivery upon exercise of the Warrants, the
number of shares of Common Stock of each class (or Other Securities) from time
to time issuable upon exercise of all Warrants at the time outstanding.  All
shares of Common Stock (or Other Securities) issuable upon exercise of any
Warrants shall be duly authorized and, when issued upon such exercise, shall be
validly issued and, in the case of shares, fully paid and nonassessable with no
liability on the part of the holders thereof.

10.  OWNERSHIP, TRANSFER AND SUBSTITUTION OF WARRANTS.

          10.1.  Ownership of Warrants.  The Company may treat the person in
whose name any Warrant is registered on the register kept at the office of the
Company maintained pursuant to Section 10.2(a) hereof as the owner and holder
thereof for all purposes, notwithstanding any notice to the contrary, except
that, if and when any Warrant is properly assigned in blank, the Company may
(but shall not be obligated to) treat the bearer thereof as the owner of such
Warrant for all purposes, notwithstanding any notice to the contrary.  Subject
to Section 8 hereof, a Warrant, if properly assigned, may be exercised by a new
holder without a new Warrant first having been issued.

          10.2.  Office; Transfer and Exchange of Warrants.

                 (a)  The Company will maintain an office (which may be an
          agency maintained at a bank) in Rochester, New Hampshire where
          notices, presentations and demands in respect of this Warrant may be
          made upon it. Such office shall be maintained at 35 Industrial Way,
          Rochester, New Hampshire 03867 until such time as the Company shall
          notify the holders of the Warrants of any change of location of such
          office within Rochester, New Hampshire.

                                      -9-
<PAGE>

                 (b)  The Company shall cause to be kept at its office
          maintained pursuant to Section 10.2(a) hereof a register for the
          registration and transfer of the Warrants. The names and addresses of
          holders of Warrants, the transfers thereof and the names and addresses
          of transferees of Warrants shall be registered in such register. The
          Person in whose name any Warrant shall be so registered shall be
          deemed and treated as the owner and holder thereof for all purposes of
          this Warrant, and the Company shall not be affected by any notice or
          knowledge to the contrary.

                 (c)  Upon the surrender of any Warrant, properly endorsed, for
          registration of transfer or for exchange at the office of the Company
          maintained pursuant to Section 10.2(a) hereof, the Company at its
          expense will (subject to compliance with Section 8 hereof, if
          applicable) execute and deliver to or upon the order of the holder
          thereof a new Warrant or Warrants of like tenor, in the name of such
          holder or as such holder (upon payment by such holder of any
          applicable transfer taxes) may direct, calling in the aggregate on the
          face or faces thereof for the number of shares of Common Stock called
          for on the face or faces of the Warrant or Warrants so surrendered.

          10.3.  Replacement of Warrants.  Upon receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of any
Warrant and upon delivery of indemnity and surety bond reasonably satisfactory
to the Company in form and amount or, in the case of any such mutilation, upon
surrender of such Warrant for cancellation at the office of the Company
maintained pursuant to Section 10.2(a) hereof, the Company at its expense will
execute and deliver, in lieu thereof, a new Warrant of like tenor and dated the
date hereof.

11.  DEFINITIONS.  As used herein, unless the context otherwise requires, the
following terms have the following respective meanings:

          Business Day:  Any day other than a Saturday or a Sunday or a day on
which commercial banking institutions in Boston, Massachusetts, New York, New
York or Rochester, New Hampshire are authorized by law to be closed.  Any
reference to "days" (unless Business Days are specified) shall mean calendar
days.

          Commission:  The Securities and Exchange Commission or any other
federal agency at the time administering the Securities Act.

          Common Stock:  As defined in the introduction to this Warrant, such
term to include any stock into which such Common Stock shall have been changed
or any stock resulting from any reclassification of such Common Stock, and all
other stock of any class or classes (however designated) of the Company the
holders of which have the right, without limitation as to amount, either to all
or to a share of the balance of current dividends and liquidating

                                      -10-
<PAGE>

dividends after the payment of dividends and distributions on any shares
entitled to preference; provided, however, that, subject to the provisions of
                        --------  -------
Section 3.1 of this Warrant, shares of Common Stock issuable on exercise of this
Warrant shall include only shares of the class designated as Common Stock of the
Company on the date hereof or any stock into which such Common Stock shall have
been changed or any stock resulting from any reclassification of such Common
Stock (provided that, if at any time there shall be more than one such resulting
class, the shares of each such class then so issuable shall be substantially in
the proportion which the total number of shares of such class resulting from
such changes and reclassifications bears to the total number of shares of all
classes resulting from all such changes and reclassifications).

          Company:  As defined in the introduction to this Warrant, such term to
include any corporation which shall succeed to or assume the obligations of the
Company hereunder in compliance with Section 3 hereof.

          Current Market Price:  On any date specified herein, the average daily
Market Price during the period of the most recent 10 days, ending on such date,
on which the national securities exchanges were open for trading, except that if
no class of the Common Stock is then listed or admitted to trading on any
national securities exchange or quoted in the over-the-counter market, the
Current Market Price shall be the Market Price on such date.

          Expiration Date:  As defined in the introduction to this Warrant.

          Investors:  As defined in the introduction to this Warrant.

          Market Price:  On any date specified herein, the amount per share of
Common Stock equal to (a) the last sale price of Common Stock, regular way, on
such date or, if no such sale takes place on such date, the average of the
closing bid and asked prices thereof on such date, in each case as officially
reported on the principal national securities exchange on which Common Stock is
then listed or admitted to trading, or (b) if Common Stock is not then listed or
admitted to trading on any national securities exchange but is designated as a
national market system security by the NASD, the last trading price of Common
Stock on such date, or (c) if there shall have been no trading on such date or
if Common Stock is not so designated, the average of the closing bid and asked
prices of Common Stock on such date as shown by the NASD automated quotation
system, or (d) if Common Stock is not then listed or admitted to trading on any
national exchange or quoted in the over-the-counter market, the fair value
thereof on such date as reasonably determined in good faith by the Board of
Directors of the Company as of the date on which the determination is to be
made; provided, however, that the holder of this Warrant shall have no right to
      --------  -------
object to such determination unless such holder submits an objection in good
faith to the Board of Directors within 10 days of notice thereof.

                                      -11-
<PAGE>

          NASD:  The National Association of Securities Dealers, Inc.

          Operating Subsidiary:  As defined in the Purchase Agreement.

          Operating Subsidiary Warrant:  As defined in the Purchase Agreement.

          Other Securities:  Any stock (other than Common Stock) and other
securities of the Company or any other person (corporate or otherwise) which the
holders of the Warrants at any time shall be entitled to receive, or shall have
received, upon the exercise of the Warrants, in lieu of or in addition to Common
Stock, or which at any time shall be issuable or shall have been issued in
exchange for or in replacement of Common Stock or Other Securities, in each
case, pursuant to Section 3 hereof or otherwise in accordance with the terms
hereof.

          Person:  A corporation, an association, a partnership, a limited
liability company, an organization, a business, an individual, a government or
political subdivision thereof or a governmental agency.

          Post-Spin-Off Warrant Value:  An amount equal to the product of the
total number of shares of Common Stock for which this Warrant is exercisable as
of the time of determination specified herein multiplied by the Market Price of
                                              ----------
such shares of Common Stock as of such time.

          Purchase Agreement:  As defined in the introduction to this Warrant.

          Securities Act:  The Securities Act of 1933, or any similar federal
statute, and the rules and regulations of the Commission thereunder, all as the
same shall be in effect at the time.

          Spin-Off:  As defined in the Purchase Agreement.

          Standstill Agreement:  The Standstill Agreement, dated as of August
29, 2000, among the Company and the Investors, as from time to time in effect.

          Subsidiary Warrant Value:  An amount equal to the product of the total
number of shares of capital stock that would have been distributed in a Spin-Off
in respect of the aggregate shares of Common Stock issuable under this Warrant
if this Warrant had been exercised in full immediately prior to the record date
for such distribution, multiplied by the Market Price of such shares of capital
                       -------------
stock as of the time of determination.

          Warrant Price:  As defined in Section 2.1 hereof.

          Warrants:  As defined in the introduction to this Warrant.

                                      -12-
<PAGE>

12.  REMEDIES.  The Company stipulates that the remedies at law of the holder of
this Warrant in the event of any default or threatened default by the Company in
the performance of or compliance with any of the terms of this Warrant are not
and will not be adequate and that, to the fullest extent permitted by law, such
terms may be specifically enforced by a decree for the specific performance of
any agreement contained herein or by an injunction against a violation of any of
the terms hereof or otherwise.

13.  NO RIGHTS OR LIABILITIES AS STOCKHOLDER.  Nothing contained in this Warrant
shall be construed as conferring upon the holder hereof any rights as a
stockholder of the Company or as imposing any obligation on such holder to
purchase any securities or as imposing any liabilities on such holder as a
stockholder of the Company, whether such obligation or liabilities are asserted
by the Company or by creditors of the Company.

14.  NOTICES.  Any notice or other communication in connection with this Warrant
shall be deemed to be delivered if in writing (or in the form of a telex or
telecopy) addressed as hereinafter provided and if either (x) actually delivered
at said address (evidenced in the case of a telex by receipt of the correct
answerback) or (y) in the case of a letter, three Business Days shall have
elapsed after the same shall have been deposited in the United States mails,
postage prepaid and registered or certified:  (a) if to any holder of any
Warrant, at the registered address of such holder as set forth in the register
kept at the office of the Company maintained pursuant to Section 10.2(a) hereof;
or (b) if to the Company, to the attention of its President at its office
maintained pursuant to Section 10.2(a) hereof; provided, however, that the
exercise of any Warrant shall be effective in the manner provided in Section 1
hereof.

15.  MISCELLANEOUS.  This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.  This Warrant shall be construed and enforced in accordance with and
governed by the domestic substantive laws of the State of Delaware (without
giving effect to any choice or conflict of law provision or rule that would
cause the application of the law of any other jurisdiction).  The section
headings in this Warrant are for purposes of convenience only and shall not
constitute a part hereof.

16.  SUCCESSORS AND ASSIGNS.  Except as otherwise provided herein, all the
covenants and provisions of this Warrant by or for the benefit of the Company
and the registered holders of the Warrants shall inure to the benefit of their
respective successors and assigns.

                                      -13-
<PAGE>

                                          ENTERASYS NETWORKS, INC.



                                          By:_______________________________
                                           Title:

                                      -14-
<PAGE>

                              FORM OF SUBSCRIPTION

                 [To be executed only upon exercise of Warrant]


To ENTERASYS NETWORKS, INC.

          The undersigned registered holder of the within Warrant hereby
irrevocably exercises such Warrant for, and purchases thereunder, __________/1/
shares of the Common Stock and herewith makes payment of $        therefor, and
requests that the certificates for such shares be issued in the name of, and
delivered to                   , whose address is                    .



Dated:                               _________________________________
                                     (Signature must conform in all
                                     respects to name of holder as
                                     specified on the face of Warrant)

                                     _________________________________
                                     (Street Address)

                                     _________________________________
                                     (City)     (State)     (Zip Code)



________________________

/1/   Insert here the number of shares called for on the face of this Warrant
(or, in the case of a partial exercise, the portion thereof as to which this
Warrant is being exercised), in either case without making any adjustment for
additional shares of Common Stock or any other stock or other securities or
property or cash which, pursuant to the adjustment provisions of this Warrant,
may be delivered upon exercise.  In case of a partial exercise, a new Warrant or
Warrants will be issued and delivered, representing the unexercised portion of
the Warrant, to the holder surrendering the Warrant.


<PAGE>

                           FORM OF CONVERSION NOTICE

                [To be executed only upon conversion of Warrant]


To ENTERASYS NETWORKS, INC.

          The undersigned registered holder of the within Warrant hereby
irrevocably converts such Warrant with respect to __________/1/  shares of the
Common Stock which such holder would be entitled to receive upon the exercise
hereof, and requests that the certificates for such shares be issued in the name
of, and delivered to                   , whose address is            .



Dated:                                  _________________________________
                                        (Signature must conform in all
                                        respects to name of holder as
                                        specified on the face of Warrant)

                                        _________________________________
                                        (Street Address)

                                        _________________________________
                                        (City)     (State)     (Zip Code)

________________________

/1/    Insert here the number of shares called for on the face of this Warrant
(or, in the case of a partial conversion, the portion thereof as to which this
Warrant is being converted), in either case without making any adjustment for
additional shares of Common Stock or any other stock or other securities or
property or cash which, pursuant to the adjustment provisions of this Warrant,
may be delivered upon exercise.  In case of a partial conversion, a new Warrant
or Warrants will be issued and delivered, representing the unconverted portion
of the Warrant, to the holder surrendering the Warrant.


<PAGE>

                               FORM OF ASSIGNMENT

                 [To be executed only upon transfer of Warrant]


          For value received, the undersigned registered holder of the within
Warrant hereby sells, assigns and transfers unto                    the right
represented by such Warrant to purchase __________/1/ shares of Common Stock of
ENTERASYS NETWORKS, INC. to which such Warrant relates, and appoints
Attorney to make such transfer on the books of ENTERASYS NETWORKS, INC.
maintained for such purpose, with full power of substitution in the premises.


Dated:                                _________________________________
                                      (Signature must conform in all
                                      respects to name of holder as
                                      specified on the face of Warrant)

                                      _________________________________
                                      (Street Address)

                                      _________________________________
                                      (City)     (State)     (Zip Code)

Signed in the presence of:



__________________________


__________________________

/1/    Insert here the number of shares called for on the face of this Warrant
(or, in the case of a partial assignment, the portion thereof as to which this
Warrant is being assigned), in either case without making any adjustment for
additional shares of Common Stock or any other stock or other securities or
property or cash which, pursuant to the adjustment provisions of this Warrant,
may be delivered upon exercise.  In case of a partial assignment, a new Warrant
or Warrants will be issued and delivered, representing the unexercised portion
of the Warrant, to the holder surrendering the Warrant.