FIFTH AMENDMENT

                                       TO
                    REVOLVING CREDIT AGREEMENT (UNGUARANTEED)


     Fifth Amendment dated as of June 30, 2000 to Revolving Credit Agreement
(the "Fifth Amendment"), by and among APPNET SYSTEMS, INC., a Delaware
corporation (the "Borrower"), FLEET NATIONAL BANK (formerly known as BANKBOSTON,
N.A.) and the other lending institutions listed on Schedule 1 to the Credit
Agreement (as hereinafter defined) (the "Banks"), amending certain provisions of
the Revolving Credit Agreement dated as of January 8, 1999 (as amended and in
effect from time to time, the "Credit Agreement") by and among the Borrower, the
Banks, Fleet National Bank (formerly known as BankBoston, N.A.) as agent for the
Banks (the "Agent") and Antares Capital Corporation as co-agent for the Banks.
Terms not otherwise defined herein which are defined in the Credit Agreement
shall have the same respective meanings herein as therein.

     WHEREAS, the Borrower and the Banks have agreed to modify certain terms and
conditions of the Credit Agreement as specifically set forth in this Fifth
Amendment;

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
contained herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree as
follows:

     ss.1. Amendment to Section 10 of the Credit Agreement. Section 10.7 of the
Credit Agreement is hereby amended by deletingss.10.7 in its entirety and
restating it as follows:

          10.7. Capital Expenditures. The Borrower will not make, or permit any
     Subsidiary of the Borrower to make, Capital Expenditures, other than
     Capital Expenditures which the Majority Banks reasonably determine are made
     for nonrecurring one-time infrastructure purchases or leases by the
     Borrower, in any fiscal year that exceed, in the aggregate, $15,000,000 for
     any fiscal year.

     ss.2. Amendment to Condition in Consent Letter. Pursuant to the terms of
the Limited Consent dated as of August 16, 1999 (the "Letter"), the Borrower
agreed that it shall maintain a monthly Maximum DSO Requirement (as defined in
the Letter) of not greater than 82, which Maximum DSO Requirement shall be
tested at the end of each calendar month, at which time the Borrower shall
provide all calculations requested by the Agent and the Banks to demonstrate
such compliance. The parties hereto hereby agree that the monthly Maximum DSO
Requirement is hereby amended by deleting the number "82" which appears in such
requirement and substituting in place thereof the number "90".

<PAGE>
                                      -2-


     ss.3. Conditions to Effectiveness. This Fifth Amendment shall not become
effective until the Agent receives a counterpart of this Fifth Amendment,
executed by the Borrower, each Subsidiary and the Banks

     ss.4. Representations and Warranties. The Borrower hereby represents that,
on and as of the date hereof, each of the representations and warranties made by
it in ss.7 of the Credit Agreement remain true as of the date hereof (except to
the extent of changes resulting from transactions contemplated or permitted by
the Credit Agreement and the other Loan Documents and changes occurring in the
ordinary course of business that singly or in the aggregate are not materially
adverse, and to the extent that such representations and warranties relate
expressly to an earlier date), provided, that all references therein to the
Credit Agreement shall refer to such Credit Agreement as amended hereby. In
addition, the Borrower hereby represents and warrants that the execution and
delivery by the Borrower and its Subsidiaries of this Fifth Amendment and the
performance by the Borrower and its Subsidiaries of all of its agreements and
obligations under the Credit Agreement and the other Loan Documents as amended
hereby are within the corporate authority of each of the Borrower and its
Subsidiaries and has been duly authorized by all necessary corporate action on
the part of the Borrower and its Subsidiaries.

     ss.5. Ratification, Etc. Except as expressly amended hereby, the Credit
Agreement and all documents, instruments and agreements related thereto,
including, but not limited to the Security Documents, are hereby ratified and
confirmed in all respects and shall continue in full force and effect. The
Credit Agreement and this Fifth Amendment shall be read and construed as a
single agreement. All references in the Credit Agreement or any related
agreement or instrument to the Credit Agreement shall hereafter refer to the
Credit Agreement as amended hereby.

     ss.6. No Waiver. Nothing contained herein shall constitute a waiver of,
impair or otherwise affect any Obligations, any other obligation of the Borrower
or any rights of the Agent or the Banks consequent thereon.

     ss.7. Counterparts. This Fifth Amendment may be executed in one or more
counterparts, each of which shall be deemed an original but which together shall
constitute one and the same instrument.

     ss.8. Governing Law. THIS FIFTH AMENDMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE COMMONWEALTH OF MASSACHUSETTS
(WITHOUT REFERENCE TO CONFLICT OF LAWS).

<PAGE>

                                      -3-

     IN WITNESS WHEREOF, the parties hereto have executed this Fifth Amendment
as a document under seal as of the date first above written.

                                  APPNET SYSTEMS, INC.



                                  By: /s/
                                     ----------------------------------------
                                  Title:

                                  FLEET NATIONAL BANK (formerly
                                  know as BankBoston, N.A.)



                                  By: /s/
                                     ----------------------------------------
                                       Jay L. Massimo, Director


                                  ANTARES CAPITAL CORPORATION



                                  By: /s/
                                     ----------------------------------------
                                  Title:

<PAGE>
                                      -4-


                            RATIFICATION OF GUARANTY

     Each of the undersigned guarantors hereby acknowledges and consents to the
foregoing Fifth Amendment as of June 30, 2000 and agrees that each of the
Guaranty dated as of January 8, 1999, March 4, 1999 and March 10, 1999 from each
of the undersigned guarantors remains in full force and effect, and each of the
guarantors confirms and ratifies all of its obligations thereunder.

                                  APPNET OF MICHIGAN, INC.



                                  By: /s/
                                     -------------------------------------------
                                  Title:

                                  APPNET OF MARYLAND, INC.



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  SOFTWARE SERVICES CORPORATION



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  NEW MEDIA PUBLISHING, INC.



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  RESEARCH & PLANNING, INC.


                                  By: /s/
                                     ------------------------------------------
                                  Title:
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                                      -5-



                                  CENTURY COMPUTING, INCORPORATED



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  THE KODIAK GROUP, INC.



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  I33 COMMUNICATION CORP.



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  SIGMA6, INC.



                                  By: /s/
                                     -------------------------------------------
                                  Title:


                                  SALZINGER ACQUISITION CORP.



                                  By: /s/
                                     -------------------------------------------
                                  Title: