Document:

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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:

----------------------------------            ----------------------------------
                                               Byung C. Choi

                                       4<PAGE>

                                                                   Exhibit 10.26

                   AMENDED AND RESTATED STOCK PLEDGE AGREEMENT

         THIS AMENDED AND RESTATED STOCK PLEDGE AGREEMENT (this "Agreement") is
made as of September 20, 1999, between Byung Choi ("Pledgor") and Primix
Solutions Inc., a Delaware corporation ("Pledgee").

         Section 1. PLEDGE OF STOCK. Pledgor hereby assigns to Pledgee, and
grants to Pledgee a first priority security interest in, the Options (as
hereinafter defined) and the Stock (as hereinafter defined), to be held by
Pledgee subject to the terms and conditions hereinafter set forth, the option
agreements and/or certificates for which, accompanied by stock powers or other
appropriate instruments of assignment thereof duly executed by Pledgor, have
been delivered to Pledgee and, as to Options and Stock hereafter acquired, shall
be delivered to Pledgee. Pledgor agrees to immediately deliver any certificates
evidencing the Options and Stock upon receipt.

         Section 2. DEFINITIONS.

                  (a) The term "OPTIONS" as used herein includes the stock
option to purchase 100,000 shares of Common Stock of Primix Solutions Inc. and
any additional stock options to purchase shares of capital stock of Primix
Solutions Inc. hereafter acquired.

                  (b) The term "STOCK" as used herein includes any shares of
Common Stock of Primix Solutions Inc. issued or issuable under the Options and
any additional shares of capital stock of Primix Solutions Inc. hereafter
acquired. The term "Stock" shall further include all cash or non-cash income
from the shares of Stock pledged hereunder, all increases therein and proceeds
thereof, other than income, increases or proceeds received by Pledgor pursuant
to Section6 hereof, and any dividend paid in respect of the Stock in the form of
additional shares of stock, options to purchase stock, warrants or convertible
securities (a "NON-CASH DIVIDEND").

                  (b) The term "OBLIGATIONS" as used herein means all
indebtedness, obligations and liabilities of Pledgor to Pledgee, whether now
existing or hereafter arising, under that certain Promissory Note in the face
amount of TWO HUNDRED FIFTY THOUSAND AND 00/100 DOLLARS ($250,000.00) made by
Pledgee in favor of Pledgor as of September 20, 1999 (the "Note") and all future
advances or loans given by Pledgee to Pledgor under any other arrangements.

                  (c) The term "Event of Default" as used herein shall mean the
occurrence of any of the following events: (i) an assignment for the benefit of
creditors or commencement of any proceeding under any bankruptcy or insolvency
law by or against the Maker, (ii) the termination, for any reason, of the
Maker's employment with the Payee, (iii) a material breach of this Agreement,
(iv) the Maker shall have failed to pay the full amount of principal and accrued

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interest then outstanding on the Maturity Date (as defined in the Note), or (v)
an event of default under the Mortgage (as defined in the Note).

         Section 3. SECURITY FOR OBLIGATIONS. This Agreement, the pledge of the
Options and Stock hereunder and the Mortgage are made in favor of Pledgee as
security for the Obligations.

         Section 4. LIQUIDATION, RECAPITALIZATION, ETC. Any sums paid upon or
with respect to any of the Stock upon the liquidation or dissolution of the
issuer thereof shall be paid over to Pledgee to be held by it as security for
the Obligations; and in case any distribution of capital shall be made on or in
respect of any of the Stock or any property shall be distributed upon or with
respect to any of the Stock pursuant to the recapitalization or reclassification
of the capital of the issuer thereof or pursuant to the reorganization thereof,
the capital or property so distributed shall be delivered to Pledgee to be held
by it as security for the Obligations. All sums of money and property paid or
distributed in respect of the Stock upon such a liquidation, dissolution,
recapitalization or reclassification which are received by Pledgor shall, until
paid or delivered to Pledgee, be held in trust for Pledgee as security for the
Obligations.

         Section 5. WARRANTY OF TITLE. Pledgor warrants that: (a) Pledgor is the
lawful, record and beneficial owner of the Options and Stock; (b) the Options
and Stock are not subject to any pledge, lien, security interest, charge,
option, restrictions or other encumbrances except the security interest created
by this Agreement; (c) Pledgor has the power, authority and legal right to
pledge all of such Options and Stock pursuant to this Agreement; (d) no person
has any present or future right (conditional, preemptive or otherwise) to
acquire, vote, register or restrict the transfer of the Options and Stock; and
(e) the execution and delivery of this Agreement and the pledging of the Options
and Stock hereunder do not contravene any law or any rule or regulation
thereunder or any judgment, decree or order of any tribunal, or conflict with,
or result in a breach of or default under, or give rise to acceleration under,
any agreement or instrument to which Pledgor is a party or any of Pledgor's
property is bound.

         Section 6. DIVIDENDS, VOTING, ETC., PRIOR TO MATURITY. So long as no
Event of Default has occurred and is continuing, Pledgor shall be entitled to
receive all cash dividends, if any, paid in respect of the Stock, and to vote
outstanding shares of the Stock and to give consents, waivers and ratifications
in respect of the Stock, PROVIDED that no vote shall be cast, or consent, waiver
or ratification given or action taken which would be inconsistent with or
violate any provisions of this Agreement, and PROVIDED FURTHER, that upon an
Event of Default, Pledgee may cause the Options and Stock to be transferred into
its own name as collateral security. All such rights of Pledgor to receive cash
dividends shall cease in case an Event of Default shall have occurred and be
continuing. All such rights of Pledgor to vote and give consents, waivers and
ratifications with respect to the Stock shall, at Pledgee's option, as evidenced
by Pledgee notifying Pledgor of such election, cease in case an Event of Default
shall have occurred and be continuing. In the event that a Non-Cash Dividend
shall be paid in respect of the Stock, Pledgor shall promptly

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deliver to Pledgee the certificates issued in connection with such Non-Cash
Dividend, if any, together with stock powers or other appropriate instruments of
assignment thereof duly executed by Pledgor.

         Section 7. REMEDIES. If an Event of Default shall have occurred and be
continuing, Pledgee shall thereafter have the following rights and remedies (to
the extent permitted by applicable law) in addition to the rights and remedies
of a secured party under the Uniform Commercial Code of Massachusetts, all such
rights and remedies being cumulative, not exclusive, and enforceable
alternatively, successively or concurrently, at such time or times as Pledgee
deems expedient:

                  (a) if Pledgee so elects and gives notice of such election to
Pledgor, Pledgee may vote any or all outstanding shares of the Stock and give
all consents, waivers and ratifications in respect of the Stock and otherwise
act with respect thereto as though it were the outright owner thereof (Pledgor
hereby irrevocably constituting and appointing Pledgee the proxy and
attorney-in-fact of Pledgor, with full power of substitution, to do so);

                  (b) Pledgee may demand, sue for, collect or make any
compromise or settlement Pledgee deems suitable in respect of the Options and
Stock;

                  (c) Pledgee may sell, resell, assign and deliver, or otherwise
dispose of any or all of the Stock, for cash and/or credit and upon such terms
at such place or places and at such time or times and to such persons, firms,
companies or corporations as Pledgee thinks expedient, all without demand for
performance by Pledgor or any notice or advertisement whatsoever except such as
may be required by law; and

                  (d) Pledgee may cause all or any part of the Stock held by it
to be transferred into its name or the name of its nominee or nominees or cancel
all or any part of the Options.

         Pledgee may enforce its rights hereunder without any other notice and
without compliance with any other condition precedent now or hereunder imposed
by statute, rule of law or otherwise (all of which are hereby expressly waived
by Pledgor, to the fullest extent permitted by law). Pledgor acknowledges that
ten (10) calendar days' notice of any public sale or of that date on or after
which a private sale may be effected is reasonable notice. Pledgee may buy any
part or all of the Stock at any public sale, and if any part or all of the Stock
is of a type customarily sold in a recognized market or is of the type which is
the subject of widely- distributed standard price quotations, Pledgee may buy at
a private sale and may make payments thereof by any means. Pledgee may apply the
cash proceeds actually received from any sale or other disposition of the Stock
to the reasonable expenses of retaking, holding, preparing for sale, selling and
the like, to reasonable attorneys' fees, and all legal expenses, travel and
other expenses which may be incurred by Pledgee in attempting to collect the
Obligations or to enforce

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this Agreement or in the prosecution or defense of any action or proceeding
related to the subject matter of this Agreement; and then to the Obligations,
and any surplus shall be paid to Pledgor.

         Pledgor recognizes that Pledgee may be unable to effect a public sale
of the Stock by reason of certain prohibitions contained in the Securities Act
of 1933, as amended, but may be compelled to resort to one or more private sales
thereof to a restricted group of purchasers or to a public sale which is
restricted to residents of the Commonwealth of Massachusetts. Pledgor agrees
that any such private sales or such restricted public sales may be at prices and
other terms less favorable to the seller than if sold at public sales and that
such private sales or such restricted public sales shall not by reason thereof
be deemed not to have been made in a commercially reasonable manner. Pledgee
shall be under no obligation to delay a sale of any of the Stock for the period
of time necessary to permit the issuer of such securities to register such
securities for public sale under the Securities Act of 1933, as amended, even if
the issuer would agree to do so.

         In all events, Pledgee shall give Pledgor not less than ten (10)
calendar days' written notice of any proposed disposition of the Stock or
cancellation of the Options.

         Section 8. MARSHALLING. Pledgee shall not be required to marshal any
present or future security for (including but not limited to this Agreement and
the Options and Stock pledged hereunder), or guarantees of, the Obligations, or
to resort to such security or guarantees in any particular order; and all of its
rights hereunder and in respect of such security and guarantees shall be
cumulative and in addition to all other rights, however existing or arising. To
the extent that he lawfully may, Pledgor hereby agrees that he will not invoke
any law relating to the marshalling of collateral which might cause delay in or
impede the enforcement of Pledgee's rights under this Agreement or under any
other instrument evidencing any of the Obligations or under which any of the
Obligations is outstanding or by which any of the Obligations is secured or
guaranteed, and to the extent that it lawfully may Pledgor hereby irrevocably
waives the benefits of all such laws.

         Section 9. PLEDGOR'S OBLIGATIONS NOT AFFECTED. The obligations of
Pledgor hereunder shall remain in full force and effect without regard to, and
shall not be impaired by: (a) any bankruptcy, insolvency, reorganization,
arrangement, readjustment, composition, liquidation or the like of Pledgee; (b)
any exercise or nonexercise, or any waiver, by Pledgee of any right, remedy,
power or privilege under or in respect of the Obligations or any of any security
therefor (including this Agreement); (c) any amendment to or modification of any
instrument (other than this Agreement) securing any of the Obligations; or (d)
the taking of additional security for, or any guaranty of, any of the
Obligations or the release or discharge or termination of any security or
guaranty for any of the Obligations; whether or not Pledgor shall have notice or
knowledge of any of the foregoing.

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<PAGE>

         Section 10. TRANSFER, ETC., BY PLEDGOR. Without the prior written
consent of Pledgee, Pledgor will not sell, assign, transfer or otherwise dispose
of, grant any option with respect to, or pledge or grant any security interest
in or otherwise encumber any of the Options and Stock or any interest therein,
except for the pledge thereof provided for in this Agreement.

         Section 11. FURTHER ASSURANCES. Pledgor will, from time to time,
execute and deliver to Pledgee all such other and further instruments and
documents and take or cause to be taken all such other and further action as
Pledgee may reasonably request in order to effect and confirm more securely in
Pledgee all rights contemplated in this Agreement.

         Section 12. PLEDGEE'S EXONERATION. Under no circumstances shall Pledgee
be deemed to assume any responsibility for or obligation or duty with respect to
the Options and Stock or any matter or proceedings arising out of or relating
thereto, other than to exercise reasonable care in the physical custody of the
Options and Stock. Pledgee shall not be required to take any action of any kind
to collect, preserve or protect its or Pledgor's rights in the Options and Stock
or against other parties thereto, other than to exercise reasonable care in the
physical custody of the Options and Stock.

         Section 13. NO WAIVER, ETC. No act, failure or delay by Pledgee shall
constitute a waiver of its rights and remedies hereunder or otherwise. No single
or partial waiver by Pledgee of any default or right or remedy which it may have
shall operate as a waiver of any other default, right or remedy or of the same
default, right or remedy on a future occasion. Pledgor hereby waives
presentment, notice of dishonor and protest of all instruments, included in or
evidencing any of the Obligations, and any and all other notices and demands
whatsoever (except as expressly provided herein).

         Section 14. NOTICE, ETC. All communications herein provided shall be in
writing and shall be sufficient if sent by United States mail, registered or
certified, postage prepaid, delivered by messenger, overnight delivery service
or telecopier, addressed as follows:

       If to Pledgor, at the address set forth below Pledgor's signature.

       If to Pledgee:            Primix Solutions Inc.
                                 One Arsenal Marketplace, 2nd Floor
                                 Watertown, MA 02472
                                 Telecopier:  (617) 923-6565
                                 Attention:  Chief Financial Officer

or to such other address as the party to receive any such communication or
notice may have designated by written notice to the other party.

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<PAGE>

         Any notice given pursuant to this Section shall be deemed to have been
given and received when actually delivered, upon receipt of electronic
confirmation if by telecopier, one business day after dispatch by a recognized
overnight delivery service, or three business days after mailing by certified or
registered mail with proper postage affixed and return receipt requested.

         Section 15. TERMINATION. This Agreement shall terminate at such time as
all of the Obligations shall have been paid in full, and upon such termination,
Pledgor shall be entitled to the return of such Options and Stock in the
possession or control of Pledgee as has not theretofore been disposed of
pursuant to the provisions hereof and as to which Pledgee has not received
notice of a junior pledge, together with any moneys and other property of
Pledgor at the time held by Pledgee hereunder.

         Section 16. MISCELLANEOUS PROVISIONS.

                  (a) Neither this Agreement nor any term hereof may be changed,
waived, discharged or terminated except by a written instrument expressly
referring to this Agreement and to the provisions so modified or limited, and
executed by the party to be charged.

                  (b) This Agreement is personal and may not be assigned by
Pledgor. This Agreement and all obligations of Pledgor hereunder shall be
binding upon his heirs, executors and administrators. Pledgee shall have the
right to assign this Agreement, without any restriction, and Pledgee's rights
and remedies under this Agreement shall inure to the benefit of its assigns and
successors by way of merger, consolidation or sale of substantially all of the
assets or stock of Pledgee.

                  (c) This Agreement and the obligations of Pledgor hereunder
shall be governed by and construed in accordance with the laws of The
Commonwealth of Massachusetts.

                  (d) The descriptive section headings have been inserted for
convenience of reference only and do not define or limit the provisions hereof.
If any term of this Agreement shall be held to be invalid, illegal or
unenforceable, the validity of all other terms hereof shall be in no way
affected thereby, and this Agreement shall be construed and be enforceable as if
such invalid, illegal or unenforceable term had not been included herein.

                  (e) This Agreement may be executed in counterparts, each of
which shall be deemed an original and all of which together shall be deemed to
be one and the same instrument.

                  (f) To the extent permitted by applicable law, Pledgor hereby
waives trial by jury in any proceeding brought for the interpretation or
enforcement of this Agreement or for a determination of the rights of the
parties hereunder.

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<PAGE>

         Section 17. CONSENT TO JURISDICTION. PLEDGOR AND PLEDGEE IRREVOCABLY
CONSENT AND SUBMIT TO THE JURISDICTION OF THE UNITED STATES DISTRICT COURT FOR
THE DISTRICT OF MASSACHUSETTS, AND THE COURTS OF THE COMMONWEALTH OF
MASSACHUSETTS IN CONNECTION WITH ANY ACTION, PROCEEDING OR CLAIM ARISING OUT OF
OR RELATING TO THIS AGREEMENT AND/OR ANY INSTRUMENT OR DOCUMENT REQUIRED HEREBY
OR INCIDENT OR COLLATERAL HERETO.

                         [NO FURTHER TEXT ON THIS PAGE]

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<PAGE>

         IN WITNESS WHEREOF, Pledgor and Pledgee have caused this Agreement to
be duly executed as of the date first above written.

                                     "PLEDGOR"

                                      ------------------------------------
                                      Byung Choi

                Address:              12 Canterbury Lane
                                      Hopkinton, Massachusetts 01748

                                     "PLEDGEE"

                                      PRIMIX SOLUTIONS INC.

                                      By:
                                        -----------------------------------
                                        Name:
                                        Title:

                                        8

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