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                                                                   Exhibit 10.25
                                 PROMISSORY NOTE

$250,000.00                                            As of September 20, 1999


         FOR VALUE RECEIVED, Byung C. Choi, an individual with an address of 12
Canterbury Lane, Hopkinton, Massachusetts 01748 (the "Borrower"), promises to
pay to the order of Primix Solutions, Inc., a Delaware corporation (together
with any successor holder or holders of this Note, the "Lender") at its office
at One Arsenal Marketplace, Watertown, Massachusetts 02472, or such other place
as Lender may designate, the principal sum of Two Hundred Fifty Thousand and
00/100 Dollars ($250,000.00), or so much thereof as shall be advanced hereunder,
together with interest thereon, as hereinafter set forth.

         Interest on the principal balance of this Note from time to time
outstanding shall accrue from the date hereof until September 30, 2002 at the
rate of seven percent (7.00%) per year. Interest only shall be payable quarterly
in arrears in equal installments of Four Thousand Four Hundred Twenty-Three and
61/100 Dollars ($4,423.61) on the first day of the first month of each quarter
(a "Payment Date") of each year (a "Loan Year") beginning October 1 and ending
September 30, beginning with the first day of January, 2000. Interest shall be
computed on the basis of a three hundred and sixty (360)-day year and shall be
paid for the actual number of days on which principal is outstanding. On January
1, 2000, the Borrower shall pay Lender, in addition to the installment due for
the first quarter of the first Loan Year, an amount equal to the interest on the
principal balance of this Note that shall have accrued from the date hereof
through September 30, 1999 at the rate of seven percent (7.00%) per year.

         Interest on the principal balance of this Note from time to time
outstanding from October 1, 2002 until September 30, 2004 (the "P&I Date") shall
accrue at a variable annual rate which shall equal the "Prime Rate," as
hereinafter defined, plus two percentage points (2%) (the "Base Rate"). Subject
to any change in the Prime Rate, interest only shall be payable quarterly in
arrears in equal installments on each Payment Date of each Loan Year, beginning
with the first day of January, 2003. Interest shall be computed on the basis of
a three hundred and sixty (360)-day year and shall be paid for the actual number
of days on which principal is outstanding.

         Beginning on the day immediately following the P&I Date, interest on
the principal balance of this Note shall accrue at the Base Rate. Subject to any
change in the Prime Rate, interest shall be payable quarterly in arrears in
equal installments on each Payment Date of each Loan Year, beginning with the
first day of January, 2005. Interest shall be computed on the basis of a three
hundred and sixty (360)-day year and shall be paid for the actual number of days
on which principal is outstanding. In addition, beginning on the day immediately
following the P&I Date, the outstanding principal balance of this Note shall be
payable quarterly in arrears in equal installments of Two Thousand Five Hundred
and 00/100 Dollars ($2,500.00) on each Payment Date of each Loan Year, beginning
with the first day of January, 2005.


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         In any event, the entire outstanding principal balance of this Note,
together with any accrued interest and other charges as may be due hereunder,
shall be paid on September 30, 2029 (the "Maturity Date").

         In the event that any regularly scheduled payment due hereunder is not
paid within fifteen (15) days after the date it is due, Lender shall have the
right, in addition to any other rights hereunder, to collect a late charge as
compensation for increased costs of administering such late payment. Such late
charge shall be in an amount equal to five percentage points (5%) of the amount
of such late payment, and shall be due and payable upon demand.

         In the event that (i) any payment due hereunder is not paid within
fifteen (15) days after the date it is due or upon a default under the mortgage
securing this Note (the "Mortgage"), that certain Amended and Restated Stock
Pledge Agreement dated the date hereof or under any other instrument executed by
Borrower in connection with the loan evidenced by this Note (together with this
Note and the Mortgage, the "Loan Documents") which default is not cured within
the applicable grace period, if any, or (ii) the termination, for any reason or
no reason, of Borrower's employment with Lender, Lender, at its option, may
declare immediately due and payable the entire outstanding balance of principal
and interest, together with all other charges which Lender may be entitled. If
this Note is so accelerated or any amounts due hereunder are not paid on the
Maturity Date, all amounts due hereunder shall, after such acceleration or such
Maturity Date, as the case may be, bear interest at the Prime Rate plus five
percentage points (5%) per year, until paid.

         On any interest payment date, the outstanding balance of principal due
hereunder may be prepaid in whole or in part in multiples of One Thousand
Dollars ($1,000.00), provided that at least thirty (30) days' prior written
notice of such prepayment shall have been given to Lender.

         As used herein, the term "Prime Rate" shall mean the rate of interest
announced or published by Lender's primary bank as its prime rate on the first
day of the first month of each quarter of each Loan Year, beginning with the
first day of October, 1999. In the event that the Prime Rate changes from
quarter to quarter, the interest rate under this Note shall be adjusted to
reflect any change in the Prime Rate as of the date of such change, and the
amount of the equal quarterly payments of interest subsequently becoming due
under this Note shall be adjusted accordingly to provide, as nearly as possible,
for the full amortization of the remaining principal amount hereof over the
remaining term of this Note. In the event the Prime Rate is no longer published
or announced or becomes unascertainable for any reason, Lender shall designate a
comparable reference rate which shall be deemed the Prime Rate hereunder.

         Any notice required or permitted to be delivered hereunder shall be in
writing and shall be deemed to be delivered on the earlier of (i) the date
received, or (ii) the date of delivery, refusal, or non-delivery indicated on
the return receipt, if deposited in a United States Postal Service depository,
postage prepaid, sent registered or certified mail, return receipt requested,
addressed to the party to receive the same at the address of such party set
forth at the beginning of this Note, or at such other address as may be
designated in a notice delivered or mailed as herein provided.


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         Borrower agrees to pay all charges (including reasonable attorneys'
fees) of Lender in connection with the collection and/or enforcement of this
Note or any other Loan Document or in protecting or preserving the security for
this Note, whether or not suit is brought against Borrower.

         The failure of Lender at any time to exercise any option or right
hereunder shall not constitute a waiver of Lender's right to exercise such
option or right at any other time.

         Borrower hereby waives presentment, demand, notice, protest and all
other suretyship defenses generally and agrees that (i) any renewal, extension
or postponement of the time of payment or any other indulgence, (ii) any
modification, supplement or alteration of any of the Borrower's obligations
undertaken in connection with this Note or any of the other Loan Documents, or
(iii) any substitution, exchange or release of collateral or the addition or
release of any person or entity primarily or secondarily liable, may be effected
without notice to Borrower and without releasing Borrower from any liability
hereunder.

         This Note shall be governed by, construed, and enforced in accordance
with the laws of The Commonwealth of Massachusetts. If any provision of this
Note is held to be invalid or unenforceable by a court of competent
jurisdiction, the other provisions of this Note shall remain in full force and
effect. If the payment of any interest due hereunder would subject Lender to any
penalty under applicable law, then the payments due hereunder shall be
automatically reduced to what they would be at the highest rate authorized under
applicable law.

         This Note is secured by, among other things, a mortgage of real estate
located at 12 Canterbury Lane, Hopkinton, Middlesex County, Massachusetts, and
recorded with Middlesex County Registry of Deeds.

         This Note shall have the effect of an instrument under seal.

Witness:                                      Borrower:


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                                               Byung C. Choi



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