Exhibit 10.6

                           AMENDMENT NO. 5 TO LEASE


1.   Parties.
     ------- 

     This Amendment, dated as of August 12, 1995, is between North Andover Mills
Realty Limited Partnership ("Landlord") and FTP Software, Inc. ("Tenant").

2.   Recitals.
     -------- 

     2.1  Landlord and Tenant have entered into a Lease, dated November 19,
1991, as amended, for space at North Andover Mills in North Andover,
Massachusetts (the "Lease"). Unless otherwise defined, terms used in this
Amendment have the same meanings as those used in the Lease.

     2.2  Tenant wants to lease additional space ("the New Space") consisting of
the 4th floor of Building 1 and a portion of the 4th Floor of Building 32 as
crosshatched in Exhibit "A" attached hereto and incorporated herein by this
reference, and is agreed to contain 9,679 square feet of rentable area.  To
accomplish this and other matters, for Ten and No/100 Dollars ($10.00) and other
good and valuable consideration, the receipt and sufficiency of which is
acknowledged, the parties agree and the Lease is amended as follows,
notwithstanding anything to the contrary:

3.   Amendments.
     ---------- 

     3.1  "New Space Start Date" means August 12, 1995.  As of the New Space
Start Date, and continuing through and until the date that the Lease expires or
terminates with respect to the New Space:

          (a)   In Section 1.1(c), the Premises subject to the Lease will
include the New Space and therefore the agreed rentable area of the Premises
will be increased from 126,266 square feet to 134,945 square feet.

          (b)   In Section 1.1(f), Tenant's Percentage will be increased from
20.22% to 21.61%.

          (c)   The monthly base rent for the New Space will be the amounts set
forth below, prorated for any partial month.



 
          Period                 Monthly Amount
          ------                 --------------
                                        
          8/12/95 - 8/11/96          $4,340
          8/12/96 - 8/11/97          $4,514
          8/12/97 - 8/11/98          $4,694


 


                                   
          8/12/98 - 8/11/99          $4,882
          8/12/99 - 8/11/2000        $5,077
          8/12/2000 - 8/11/2001      $5,280
          8/12/2001 - 8/31/2002      $5,491


          (d) During the term of the Lease with respect to the New Space only,
Tenant will have the right to park an additional 24 cars in the project east of
High Street, but subject in all respects to Section 15.2 of the Lease (other
than the provision of such Section specifying the maximum number of Tenant's
parking spaces). If and when the Lease terminates with respect to the New Space,
Tenant will no longer be entitled to the additional parking set forth in this
clause.

     3.2  The term of the Lease with respect to the New Space only will expire
and terminate on the earliest of: August 31, 2002; the expiration of termination
of the Lease; or the termination of the Lease with respect to the New Space
pursuant to the "Cancellation Option" as described below.  There will be no
right to extend the Lease term with respect to the New Space.  Landlord grants
to Tenant an option (the "Cancellation Option") to terminate the Lease term (and
Tenant's obligations hereunder) solely with respect to the New Space, which may
be exercised only by Tenant delivering to Landlord at any time at least six (6)
months prior written notice of such termination.  On or before the effective
termination date, Tenant shall vacate and surrender possession of the New Space,
remove all of its personal property therefrom and repair any damage thereto
(except for reasonable wear and tear and casualty damage).

     3.3  Tenant accepts the New Space absolutely "as is" and with all faults in
all respects, in each case as of the New Space Start Date.  Tenant will be
solely responsible, at its expense, for providing all necessary work and
services to construct all necessary improvements to or that are necessary in
connection with the New Space (including, without limitation, submetering the
New Space for electricity and any base building improvements) to the equivalent
fit, finish and specifications as the rest of the Premises.  All work will be
done diligently and in a good and workmanlike manner, using new materials and in
compliance with all applicable Laws and the terms of the Lease.  Tenant's work
will include, without limitation, all necessary hookups, connections and tie-
ins, all necessary drawings, plans and engineering, and securing all necessary
permits, inspections, approvals and a final Certificate of Occupancy (if needed)
from the Town of North Andover.  Tenant's work and the plans and specifications
therefor will be subject to  the prior review and approval (which approval shall
not be unreasonably withheld) of and coordination and supervision by Landlord or
its representatives and will be performed so as not to damage the rest of the
Project or its Systems and Equipment.

     3.4  Landlord will not be required to, and Tenant will be solely
responsible for paying, and will indemnify, defend and hold Landlord and its
Affiliates harmless from, all brokerage fees, commissions or similar charges,
and any and all claims [_] in connection


                                      -2-

 
with this transaction from anyone that Tenant has engaged or dealt with or that
claims by, under, through or as a result of contact with Tenant.  Tenant
acknowledges that it will be paying consideration to CRF Partners, Inc. in
connection with this transaction.

4.   No Other Changes.
     ---------------- 

     Except as set forth above, the Lease remains unchanged and in full force
and effect and there are no defaults by Landlord or Tenant thereunder.


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     IN WITNESS WHEREOF, intending to be legally bound, the parties have
executed this Amendment under seal as of the date first set forth above.


WITNESS:                         FTP SOFTWARE, INC.


/s/ Lisa M. McGrath              By:  /s/ Robert W. Goodnow, Jr.
- ---------------------------          ------------------------------------
Name Printed:                    Name:    Robert W. Goodnow, Jr.
Lisa M. McGrath                  Title:   Vice President of Finance
                                 Authorized Signatory



WITNESS:                         NORTH ANDOVER MILLS REALTY
                                 By:  Niuna-North Andover, Inc., general partner


/s/ Carolyn Grover               By: /s/ Martin Spagat
- ---------------------------         -------------------------------------
Name Printed:                    Name:   Martin Spagat
Carolyn Grover                   Title:  Vice President
                                 Authorized Signatory


WITNESS:                         By:  CIIF Associates, a Massachusetts 
                                        Partnership, general partner

                                 By:  Copley Advisors, Inc., managing general
                                        partner

  /s/ Robert J. Kalinowski       By: /s/ John J. Moynihan
 --------------------------         -------------------------------------
Name Printed:                    Name:   John J. Moynihan
Robert J. Kalinowski             Title:    Vice President
                                 Authorized Signatory


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                                  EXHIBIT "A"
                                  -----------

                                    PREMISES

                                   4th FLOOR







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                             EXHIBIT "A" CONTINUED
                             ---------------------

                             DETAIL OF BUILDING #32

                                   4TH FLOOR




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