<PAGE>
 
      SECOND AMENDMENT TO SECOND AMENDED AND RESTATED CREDIT AGREEMENT
      ----------------------------------------------------------------



                                                 Date:  September 27, 1996


     This Second Amendment of the Second Amended and Restated Credit Agreement
is made by and between Network Six, Inc., a Rhode Island corporation with a
principal place of business at 475 Kilvert Street, Warwick, Rhode Island 02886
(the "Borrower") and Citizens Trust Company, a trust company organized under the
laws of the State of Rhode Island, having its principal place of business at One
Citizens Plaza, Providence, Rhode Island 02903 (the "Lender"). Each capitalized
term used herein but not expressly defined herein shall have the respective
meanings assigned thereto in that certain Second Amended and Restated Credit
Agreement by and between the Borrower and the Lender dated as of December 16,
1994, as amended by letter agreements dated November 13, 1995 and December 15,
1995 and that certain Amendment to Second Amended and Restated Credit Agreement
dated April 10, 1996 (the "First Amendment") (collectively, as further amended,
the "Credit Agreement").

                              W I T N E S S E T H
                              -------------------

     1.   The following definitions included within Section 1.1 of the Credit
Agreement are amended to read as follows:

          (a) "Closing Date" means the date on which all the conditions
               ------------                                            
     precedent set forth in the Credit Agreement and this Amendment have been
     satisfied.
<PAGE>
 
          (b) "Credit Note" means the Amended and Restated Credit Note A dated
              -----------                                                    
     April 10, 1996 in the original face amount of $2,000,000.00, and Second
     Amended and Restated Credit Note B of dated September 27, 1996 in the
     amount of $333,768.00 made by the Borrower, payable to the order of the
     Lender.

          (c) "Notes" means Credit Note A and Credit Note B and any one or more
     of them."

     2.   Section 2.1.1 of the Credit Agreement shall be amended to
read as follows:

          "2.1.1 Credit Loans.  Provided that no Default or Event of Default
                 ------------                                               
     has occurred, Lender, subject to the terms and conditions contained in this
     Agreement, shall make Credit Loans to Borrower from time to time after
     receipt by Lender from time to time before the Credit Termination Date of a
     Request from Borrower in accordance with Article 3, during the period
                                              ---------                   
     Commencing on the Closing Date and ending on the Business Day immediately
     preceding the Credit Termination Date, in an aggregate principal amount
     outstanding not to exceed at any one time the lesser of (i) the Borrowing
     Base and (ii) the following:
<TABLE>
<CAPTION>
 
         <S>                        <C>
          (A) September 27, 1996     $2,133,768.00
 
          (B) October 31, 1996       $2,083,768.00
 
          (C) November 30, 1996      $1,883,768.00
 
          (D) December 31, 1996      $1,658,768.00
 
</TABLE>

                                      -2-
<PAGE>
 
Either the presentation to Lender of a check drawn by Borrower against one of
the accounts described on Exhibit H (a "Check Request"), or receipt by Lender of
                          ---------                                             
a written request in the form of Exhibit C fully completed shall be deemed a
                                 ---------                                  
Request.  Upon receipt of a Request, and subject to the terms and condition of
this Agreement, Lender shall make Credit Loans to Borrower in such amounts as
are necessary to Cover the amount of said Requests, and such proceeds shall be
transferred to the account(s) Corresponding to those upon which said Check
Requests were presented.  The Credit Loans shall be evidenced by the Credit Note
(completed and duly executed by Borrower in accordance with this Agreement),
delivered to Lender on the Closing Date in accordance with Article 3, in the
                                                           ---------        
principal amount equal to the amount of the Credit Commitment.  The Credit
Commitment, and any obligations of Lender to make Credit Loans to Borrower
pursuant to the terms hereof shall terminate the Business Day immediately
preceding the Credit Termination Date.

NOTWITHSTANDING ANYTHING TO THE CONTRARY CONTAINED IN THE FINANCING DOCUMENTS,
THE OUTSTANDING PRINCIPAL BALANCE OF THE CREDIT LOANS AND ALL ACCRUED INTEREST
AND FEES THEREON SHALL BE DUE AND PAYABLE ON THE EARLIER OF THE CREDIT
TERMINATION DATE AND THE EXERCISE OF ANY OF LENDER'S REMEDIES UNDER SECTION 7."

     3.   Section 5.1.16 of the Agreement shall be amended to read as
follows:

          Section 5.1.16 Hawaii Contract.  (a) Keep Lender informed and submit
                        --------------- 
     to Lender promptly any and all material Correspondence, agreements,
     amendments, transcripts,

                                      -3-
<PAGE>
 
       conversations and such other documents concerning the "Hawaii
       Contract". As used herein the Hawaii Contract shall mean and refer to
       Contract 36064 between Borrower and the State of Hawaii.

          (b) With reference to those Certain payments (the "Walk-through
       Receivables") pertaining to the so-called walk-through phase of the
       Hawaii Contract, the Borrower represents that CBSI has agreed to
       undertake and complete this phase of the contract so long as it may
       receive payment directly from the State of Hawaii. Both the Borrower and
       CBSI acknowledge and agree that the Lender has a valid existing first
       security interest in all accounts receivable including the so-called
       "Walk-through Receivables". The Lender shall agree that provided that
       there shall have not occurred a Default or an Event of Default, and
       subject to receipt by the Lender of additional security in an amount and
       of a nature acceptable to the Lender in its discretion, CBSI may directly
       receive payment of the Walk-through Receivables. The Borrower and CBSI
       shall each represent an warrant to the Lender the specific tasks to be
       performed under this contract phase and shall keep a separate record of
       billings and collections thereunder. CBSI shall agree to immediately
       repay the Lender any amounts CBSI may receive from the State of Hawaii
       other than designated "Walk-through Receivables."

          (c) The Borrower further acknowledges that the Walk-through
       Receivables and Earned but Unbilled Revenue related

                                      -4-
<PAGE>
 
      to the walk-through phase of the Hawaii Contract shall be excluded from
      the Borrowing Base calculation. The foregoing notwithstanding, valid and
      undisputed Receivables and Earned but Unbilled Revenue due to the Borrower
      from CBSI for time and material provided under the walk-through phase may
      be included in the Borrowing Base calculation.

      4.  Section 5.3 of the Credit Agreement is hereby amended by adding the
following Section 5.3.14

          5.3.14 The Borrower shall provide to the Lender on a weekly basis, on
      Monday of each week, an accounts receivable aging, summary of Earned but
      Unbilled Revenue and a Borrowing Base Certificate as of the immediately
      preceding Friday. The summary of Earned but Unbilled Revenue is a fixed
      number based upon the prior months closing balance of this account. The
      monthly updated figure for Earned but Unbilled Revenue shall be due within
      ten days of the close of the previous month.

      5.  Borrower agrees that any proceeds received from any federal or state
income tax refund and/or receivable shall be paid directly to Lender. The
refund/receivable shall be applied by Lender as an additional permanent
principal reduction of the maximum Credit Commitment. The Permanent Reduction is
an additional and unscheduled reduction of the maximum Credit Commitment and is
in addition to and not in substitution of any permanent principal paydown as
required to reduce the maximum Credit Commitment by the dates outlined in
Section 2.1.1, above. The Borrower shall be required to reduce the principal
balance of

                                      -5-
<PAGE>
 
the Credit Loans to the levels outlined in Section 2.1.1 without regard to any
payment under this Paragraph 5.

     6.   Notwithstanding any provision in this Amendment, the Credit
Agreement or any Note, or in any instrument securing the Notes, the total
liability for payments legally regarded as interest shall not exceed the maximum
limits imposed by applicable law, and any payment of same in excess of the
amount allowed thereby shall, as of the date of such payment, automatically be
deemed to have been applied to the payment of the principal indebtedness
evidenced hereby, or, if same has been fully repaid, shall be repaid to Borrower
upon demand. Any notation or record of Lender with respect to such required
application which is inconsistent with the provisions of this paragraph shall be
disregarded for all purposes and shall not be binding upon either Borrower or
Lender.

     7.   The Borrower hereby restates and reaffirms all terms and conditions
contained in the Credit Agreement, as modified hereby, including all affirmative
and negative covenants set forth therein, as if made as of the date hereof.

     8.   There is no basis nor set of facts on which any amount (or any
portion thereof) owed by the Borrower to Lender (including any under the Notes)
could be reduced, offset, waived or forgiven; nor is there any claim,
counterclaim, or defense (or) other right, remedy, or basis having a similar
effect) available to the Borrower with respect to the Notes or any other
liability of the Borrower to

                                      -6-
<PAGE>
 
Lender; nor is there any basis on which the terms and conditions of any
indebtedness of the Borrower to Lender could be claimed to be or is other than
as stated on the written instruments which evidence such indebtedness.

     9.   As further consideration or the Lender agreeing to the restructuring
contemplated herein, the Borrower agrees to revise the exercise price of the
Warrant Shares granted to the Lender pursuant to that certain Warrants to
Purchase Common Stock of Network Solutions, Inc. dated November 23, 1993, from
$10.00 per share to $4.00 per share. The documents effecting this repricing
shall be prepared by counsel to the Borrower and shall be in form and substance
satisfactory to the Lender and the Lender's counsel.

     10.  The Borrower shall pay on demand all costs and expense of Lender in
connection with the preparation, execution, and delivery of this Agreement and
of any other documents and agreements between the Borrower and Lender, whether
now existing or hereafter arising, and all other expenses which may be incurred
by Lender in preparing or amending this Agreement and all other agreements,
instruments, and documents related thereto, or otherwise incurred with respect
to the Liabilities. The Borrower specifically authorizes Lender to pay all such
fees and expenses and at Lender's discretion, without notice, to add such fees
and expenses to any loan which the Borrower may have with Lender or to charge
the same to any account of the Borrower with Lender.

     11.  The Borrower respectively releases and forever discharges Lender and
all and singular Lender's affiliates, agents employees, officers, and directors
(hereinafter, collectively, and each individually, the "Released Parties") of,
to, and from any

                                      -7-
<PAGE>
 
claim or cause of action existing as of the date hereof which the Borrower has
or to which the Borrower becomes entitled against any of the Released Parties,
whether such claim or cause of action is known, unknown, absolute, contingent,
liquidated, or unliquidated. It is the intention of the Borrower that the
release effected hereby be construed broadly in favor of the Released Parties
and that it include, without limitation, any claim or cause of action on account
of, in respect to, or arising out of the Notes, and/or the relationship of the
Borrower with Lender.

     12.  The Borrower shall indemnify, defend, and hold the Lender and any
employee, officer, or agent of the Lender (each, an "Indemnified Person")
harmless of and from any claim brought or threatened against any Indemnified
Person by the Borrower, any guarantor or endorser of the Liabilities, or any
other Person (as well as from attorneys' reasonable fees and expenses in
connection therewith) on account of the Lender's relationship with the Borrower
or any other guarantor or endorser of the Liabilities (each of which may be
defended, compromised, settled, or pursued by the Indemnified Person with
counsel of the Lender's selection, but at the expense of the Borrower) other
than any claim as to which a final determination is made in a judicial
proceeding (in which the Lender and any other Indemnified Person has had an
opportunity to be heard), which determination include a specific finding that
the Indemnified Person seeking indemnification had acted in a grossly negligent
manner or in actual bad faith.

                                      -8-
<PAGE>
 
     13. Except as modified hereby all terms and conditions of the Credit
Agreement shall remain in full force and affect.

         It is intended that this Amendment take affect as a sealed instrument.


          Witness:                           NETWORK SIX, INC.

          /s/ Lisa M. Gough                  By: /s/ Dorothy M. Cipolla 
         -------------------------------        --------------------------------
                                             Name: Dorothy M. Cipolla


                                             CITIZENS TRUST COMPANY

          /s/ Lisa M. Gough                  By: /s/ Patrick C. Joyce
         -------------------------------        --------------------------------
                                             Name: Patrick C. Joyce
          

                             STATE OF RHODE ISLAND

          Providence , ss.                                September 27, 1996
          -----------                                             


               Then personally appeared the above named Dorothy M. Cipolla, the
                                                        ------------------
          Treasurer of Network Six, Inc. and acknowledged the foregoing to be
          ---------
          the free act and deed of Network Six, Inc., before me,


                                                 /s/ Lisa M. Gough
                                                --------------------------------
                                                 Notary Public
                                                 My Commission Expires: 7-6-98

                                      -9-
<PAGE>
 
                             STATE OF RHODE ISLAND

          Providence , ss.                                September 27, 1996
          -----------                                             

              Then personally appeared the above named Patrick Joyce, the Vice
                                                       -------------       ---- 
          President of Citizens Trust Company and acknowledged the foregoing to
          ---------
          be the free act and deed of Citizens Trust Company, before me,


                                                 /s/ Lisa M. Gough
                                                --------------------------------
                                                 Notary Public
                                                 My Commission Expires: 7-6-98

                                     -10-
<PAGE>
 
                   SECOND AMENDED AND RESTATED CREDIT NOTE B
                   -----------------------------------------
      $333,768.00                                Providence, Rhode Island
                                                       September 27, 1996



               This Amended and Restated Credit Note is made by Network Six,
          Inc. (f/k/a Network Solutions, Inc.), a Rhode Island corporation (the
          "Borrower"), payable to Citizens Trust Company, a trust company
          organized and existing under the laws of the State of Rhode Island,
          with head offices at One Citizens Plaza, Providence, Rhode Island
          02903 (the "Lender").

                                   RECITALS

               The Borrower has previously executed and delivered to the Lender
          that certain credit note dated November 23, 1993 in the original
          principal amount of $1,800,000.00, as amended by a First Note
          Modification Agreement dated December 16, 1994 (as amended the "Note")

               The Borrower requested the Lender, and the Lender agreed to amend
          and restate the Note, by the execution of the Amended and Restated
          Credit Note A and the Amended and Restated Credit Note B each dated as
          of April 10, 1996.

               The Borrower has requested the Lender, and the Lender has agreed,
          subject to the terms and conditions set forth herein, to amend and
          restate Amended and Restated Credit Note B by the execution of this
          Note.

               NOW, THEREFORE, in consideration of the premises and subject to
          satisfaction of the terms and conditions set forth herein, the parties
          hereby agree to amend and restate Amended and Restated Credit Note B
          as follows:

               FOR VALUE RECEIVED, the Borrower promises to pay to the Lender in
          accordance with the Credit Agreement (defined below), the lesser of
          (i) Three Hundred Thirty Three Thousand Seven Hundred Sixty Eight and
          00/100 Dollars ($333,768.00), or (ii) the aggregate unpaid principal
          amount of all Credit Loans made by Lender to Borrower attributable to
          Credit Note B pursuant to that certain Second Amended and Restated
          Credit Agreement dated December 16, 1994, as amended by letter
          agreements dated November 13, 1995 and December 15, 1995 and as
          further amended by an Amendment to Second Amended and Restated Credit
          Agreement dated April 10, 1996, and a Second Amendment to Second
          Amended and Restated Credit Agreement of even date by and among
          Borrower and Lender, as further amended from time to time hereafter
          (the "Credit Agreement").

               Borrower shall make principal payments from time to time to
          Lender in such amounts as may be necessary, if any, so as to 
<PAGE>
 
          cause the outstanding principal amount of this Note and the
          outstanding principal balance of Credit Note A to at all times be
          below the Credit Commitment then, in effect. Borrower shall pay in
          full all unpaid principal, interest, fees and other amounts due under
          this Note and/or under the Credit Agreement on the Credit Termination
          Date, or on such earlier date as said principal, interest, fees and
          other amounts may become due and payable in full pursuant to the
          Credit Agreement.

               Borrower promises to pay to the order of Lender interest before
          and after maturity on the principal amount of this Note outstanding
          from time to time from the date hereof until payment in full of all
          principal, due under this Note, payable monthly in arrears on the last
          Business Day of each month, commencing September 30, 1996, all in
          accordance with the Credit Agreement. Interest shall accrue and be due
          and payable under this Note at the rates set forth in the Credit
          Agreement.

               This Note is Credit Note B referred to in, and is entitled to the
          benefits of, the Credit Agreement.  The applicable terms and
          provisions of the Credit Agreement are incorporated herein by
          reference as if fully set forth herein.  Each capitalized term used in
          this Note and not expressly defined in this Note shall have the
          meaning ascribed to such term in the Credit Agreement. The Credit
          Agreement, among other things, contains provisions for acceleration of
          the maturity of this Note upon the happening of certain stated events
          and also for prepayments on account of principal of this Note prior to
          the maturity of this Note upon the terms and conditions specified in
          the Credit Agreement.

               This Note is secured by the Security Documents.

               If this Note shall not be paid when due and shall be placed by
          the holder hereof in the hands of an attorney for collection, through
          legal proceedings or otherwise, Borrower will pay reasonable
          attorneys' fees to the holder hereof together with reasonable costs
          and expenses of collection.

               All interest and fees payable under or in connection with this
          Note shall be computed on the basis of the actual number of days
          elapsed using a 360-day year.

               All provisions of this Note and any other agreements between
          Borrower and Lender are expressly subject to the condition that in no
          event, whether by reason of acceleration of maturity of the
          Indebtedness evidenced by this Note or otherwise, shall the amount
          paid or agreed to be paid to Lender which is deemed interest under
          applicable law exceed the maximum permitted rate of interest under
          applicable law (the "Maximum Permitted Rate"), which shall mean the
          law in effect on the date of this Note, except that if there is a
          change in such law which results in a higher Maximum Permitted Rate,
          then this Note shall be governed by such amended law from and after
          its effective date. In the 

                                      -2-
<PAGE>
 
          event that fulfillment of any provision of this Note, or the Credit
          Agreement or any document, instrument or agreement providing security
          for this Note results in the rate of interest charged hereunder being
          in excess of the Maximum Permitted Rate, the obligation to be
          fulfilled shall automatically be reduced to eliminate such excess. If,
          notwithstanding the foregoing, Lender receives an amount which under
          applicable law would cause the interest rate hereunder to exceed the
          Maximum Permitted Rate, the portion thereof which would be excessive
          shall automatically be deemed a prepayment of and be applied to the
          unpaid principal balance of this Note to the extent of then
          outstanding Loans and not a payment of interest and to the extent said
          excessive portion exceeds the outstanding principal amount of Loans,
          said excessive portion shall be repaid to Borrower.

               Borrower expressly waives presentment, notice of acceleration and
          intent to accelerate, demand for payment and protest and notice of
          protest of non-payment.

               This Note shall for all purposes be governed by and construed in
          accordance with the local laws of the State of Rhode Island.

               Executed as a sealed instrument as of the date first above
          written.

          In the presence of:                            NETWORK SIX, INC.


          By: /s/ Lisa M. Gough                    By: /s/ Dorothy M. Cipolla
             -------------------------                --------------------------

                                      -3-
<PAGE>
 
                                NETWORK SIX INC.
                                ------- --- --- 
                            CERTIFICATE OF SECRETARY



               I, Dorothy M. Cipolla, do certify that I am the duly elected,
          qualified and acting Secretary of Network Six, Inc.. a Rhode Island
          corporation, and that on September 12, 1996, the Board of Directors of
          the corporation approved the repricing of the warrants originally
          issued to Citizens Trust Company on November 23, 1993 from an exercise
          price of $10.00 per share to $4.00 per share in consideration for the
          restructuring of the corporation's credit agreement with said Citizens
          Trust Company.

               IN WITNESS WHEREOF, I have executed this Certificate of Secretary
          on the 27 day of September, 1996.
                          

                                                        /s/ Dorothy M. Cipolla
                                                        ------------------------
                                                        Secretary
<PAGE>
 
                               NETWORK SIX, INC.
                               -----------------

                            CERTIFICATE OF SECRETARY
                            ------------------------


                I, Dorothy M. Cipolla, do hereby certify that I am the duly
          elected, qualified and acting Secretary of Network Six, Inc, (the
          "Corporation"), a Rhode Island corporation, and that on September 12,
          1996, the Board of Directors of the Corporation approved the following
          resolutions:

             RESOLVED: That the Corporation is hereby authorized to borrow from
                       Citizens Trust Company (the "Lender") the aggregate
                       principal amount of up to $2,333,768.00 and, in
                       connection therewith to execute, deliver and perform (a)
                       a Second Amendment to Second Amended and Restated Credit
                       Agreement between the Corporation and Lender pursuant to
                       which the Lender will lend to the Corporation up to
                       $2,333,768.00 (the "Credit Agreement") and (b) a Second
                       Amended and Restated Credit Note B (the "Note").

             RESOLVED: That the Chairman, President or Treasurer of the
                       Corporation be, and each of them acting alone hereby is
                       authorized to execute in the name and deliver on behalf
                       of the Corporation one or more counterparts of the Credit
                       Agreement and the Note to be in form and substance as may
                       be approved by the officer executing the same, his or her
                       execution thereof to be deemed conclusive evidence of
                       such approval and of his or her authority hereunder.

             RESOLVED: That the several officers of the Corporation be and each
                       of them acting alone hereby is authorized to execute such
                       instruments and take such other actions in the name and
                       on behalf of the Corporation as they or any one of them
                       may deem necessary or appropriate to carry out the terms
                       of the Credit Agreement and the Note, including without
                       limitation, the execution, acknowledgment and delivery of
                       any and all agreements, certificates, instruments and
                       other documents as they or any one of them shall deem
                       necessary or appropriate.


             IN WITNESS WHEREOF, I have executed this Certificate of Secretary
          on the 27 day of September, 1996.

                                                      /s/ Dorothy M. Cipolla
                                                     ------------------------
                                                     Secretary