SUPPLEMENT TO JOINT PROXY STATEMENT/PROSPECTUS OF FTP SOFTWARE, INC. AND
                FIREFOX COMMUNICATIONS INC. DATED JUNE 26, 1996
 
  This Supplement is being furnished to the stockholders of FTP Software,
Inc., a Massachusetts corporation ("FTP"), in connection with the solicitation
of proxies by the FTP Board of Directors for use at a Special Meeting of FTP
stockholders (the "FTP Meeting") to be held at 11:00 a.m., local time, on July
22, 1996, at the Andover Country Club, Andover, Massachusetts 01810, and at
any adjournments or postponements of the FTP Meeting.
 
  This Supplement is also being furnished to the stockholders of Firefox
Communications Inc., a Delaware corporation ("Firefox"), in connection with
the solicitation of proxies by the Firefox Board of Directors for use at a
Special Meeting of Firefox stockholders (the "Firefox Meeting") to be held at
9:00 a.m., local time, on July 22, 1996, at Firefox's corporate headquarters,
2953 Bunker Hill Lane, Santa Clara, California 95054, and at any adjournments
or postponements of the Firefox Meeting.
 
  This Supplement updates and supplements the Joint Proxy Statement/Prospectus
(the "Joint Proxy Statement") of FTP and Firefox dated June 26, 1996, which
has previously been mailed to the stockholders of FTP and Firefox in
connection with the proposed merger (the "Merger") of Firefox Acquisition
Corp., a wholly owned subsidiary of FTP and a Delaware corporation ("Sub"),
with and into Firefox. A proxy was enclosed with the Joint Proxy Statement and
each stockholder of FTP and Firefox was encouraged to complete and return the
proxy so that such stockholder's shares represented by the proxy could be
voted as directed by the stockholder.
 
RECENT DEVELOPMENTS
 
  FTP today reported that its revenues for the quarter ended June 30, 1996 are
estimated to be approximately $28 million. It is anticipated that there will
be a net loss reported for the quarter in the range of approximately $.08 to
$.11 per share, excluding charges associated with the cost reduction
initiatives announced on May 1, 1996, and the acquisition of Campbell
Services, Inc. in April 1996. As expected, FTP incurred a loss from operations
in the second quarter. This loss is estimated to be approximately $4 million,
excluding the aforementioned charges. Included in this estimate is
approximately $3 million of non-cash depreciation and amortization charges.
 
  FTP's revenues for the quarter, while within analysts' expectations, were at
the low end of the range of those expectations. FTP now anticipates that it
will be difficult to achieve its May 1, 1996 estimate of matching 1995 full
year revenue in 1996 included in the Joint Proxy Statement.
 
  Firefox today reported that its revenues for the quarter ended June 30, 1996
are estimated to be approximately $3.5 million. As a result, Firefox expects
to incur a loss from operations for the second quarter estimated to be in the
range of $1.7 million to $2.3 million and an estimated net loss of $.17 to
$.23 per share.
 
  These estimated results for FTP and Firefox are preliminary and based on
partial information and management assumptions that are currently available.
FTP and Firefox note that each of the above forward-looking statements is
subject to change, based on various important factors, including, without
limitation, changes in the market, technology and competition.
 
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  Another proxy is enclosed herewith. If, after reviewing the information set
forth above, a stockholder wishes to revoke such stockholder's previously
submitted proxy, the stockholder should complete, date and sign the enclosed
proxy and return it to FTP or Firefox prior to the FTP Meeting or the Firefox
Meeting, as the case may be.
 
                                          July 11, 1996