**EXHIBIT
      10.33**







**DunKnight
      Telecom Partners LLC**











January
      3, 2006





DSL.net,
      Inc.


545
      Long
      Wharf Drive


5 th Floor


New
      Haven, CT 06511


Attention:
      David F. Struwas, President & CEO





Dear
      Mr.
      Struwas:





Reference
      is made to that certain Securities Purchase Agreement (the “ Agreement ”),
      dated
      as of November 2, 2005, by and among DSL.net, Inc., a Delaware corporation
      (the
“ Company ”),
      and
      DunKnight Telecom Partners LLC. Capitalized terms used herein and not otherwise
      defined herein shall have the meanings ascribed to them in the
      Agreement.





This
      will
      confirm the parties’ agreement to effectively amend and modify certain
      provisions of the Agreement and certain of the Transaction Documents entered
      into in connection with the Agreement, as set forth in this letter agreement
      (this “ Amendment ”).





Upon
      execution and delivery of this Amendment, for valuable consideration, the
      receipt and sufficiency of which are hereby acknowledged, the parties hereto
      agree as follows, effective as of the date above written:





1. Deferral
      of Additional Investment .
      Section
      4.13 of the Agreement is hereby amended and restated to read in its entirety
      as
      follows:





“4.13.  Additional
      Investment Obligation .
      On
      February 1, 2006, provided that no material Event of Default (other than one
      arising from or under Section 7(b) of the Debentures) has occurred prior to
      such
      date which has not been previously waived or cured, each Purchaser, or its
      designees, shall be required to purchase, in the ratio of such Purchaser’s
      Subscription Amount on the Closing Date to the aggregate Subscription Amounts
      of
      all Purchasers on the Closing Date (such amount, the Purchaser’s “ Pro
      Rata Share ”),
      additional debentures totaling $5,000,000 in principal amount, for an aggregate
      purchase price of $4,000,000 (the “ Additional
      Investment ”).
      For
      the sake of clarity, the Purchaser shall be required to subscribe for the entire
      Additional Investment to the extent that it has not designated other purchasers
      or such designees fail to make their pro rata share of such investment on
      February 1, 2006. The form of Debenture used for the foregoing additional
      debentures shall be identical to the form of Debenture used at the initial
      Closing, provided, however, the maturity date in the Debentures shall be
      September 4, 2006.”








2. Extension
      of Maturity Date .
      The
      maturity date of the Debentures shall be and hereby is extended to September
      4,
      2006.





3. Conforming
      Changes .
      The
      parties hereto agree that the other operative provisions of the Transaction
      Documents shall be and hereby are amended *mutatis
      mutandis* ,
      to give
      effect to the modifications made pursuant to numbered sections 1 and 2 of this
      Amendment, above. Notwithstanding the foregoing, the parties agree to take
      such
      further actions and execute and deliver such additional instruments as shall
      be
      reasonably requested or legally required to more fully give effect to the
      transactions contemplated by this Amendment. Other than as set forth in this
      Amendment, the terms and provisions of the Agreement and the other Transaction
      Documents remain in full force and effect.





4. Waiver .
      DunKnight Telecom Partners LLC, as Purchaser under the Agreement and as Investor
      and Agent under the Security Agreement, hereby irrevocably waives any and all
      Company defaults under the Transaction Documents, if any, arising from or
      attributable to the delayed implementation by any of the Company’s banks of
      account control agreements for the benefit of the Purchaser and the Agent,
      and
      further agrees that the Company’s obligations under Section 12(d) of the
      Security Agreement with respect to the establishment of account control
      agreements shall be, and are hereby, extended until February 1, 2006.




5. Certain
      Representations and Warranties .
      DunKnight Telecom Partners LLC and, by his signature below, Keir Kleinknecht,
      as
      sole managing member of such entity, each hereby represents and warrants to
      the
      Company that (a) DunKnight Telecom Partners LLC has full right, power and
      authority to enter into this Amendment and to carry out its obligations
      hereunder, (b) this Amendment constitutes the valid and legally binding
      obligation of DunKnight Telecom Partners LLC, enforceable against it in
      accordance with its terms, and (c) DunKnight Telecom Partners LLC has or will
      have by the required funding date adequate liquid funds necessary for such
      Purchaser to make the Additional Investment in accordance with this Amendment.
      By his signature below, Keir Kleinknecht, the sole managing member of DunKnight
      Telecom Partners LLC, agrees to cause DunKnight Telecom Partners LLC to fully
      and timely perform its obligations under this Amendment.





By
      countersigning this Amendment, the Company hereby acknowledges and agrees to
      all
      of the terms and conditions hereof.





*The
      Purchaser:*





**DunKnight
      Telecom Partners LLC**




By: */s/
      Keir Kleinknecht*


Name:
      Keir Kleinknecht


Title:
      Sole Managing Member


Date:
      January 3, 2006





2


*The
      Agent:*





**DunKnight
      Telecom Partners LLC,**


as
      Agent








By: */s/
      Keir Kleinknecht*


Name:
      Keir Kleinknecht


Title:
      Sole Managing Member


Date:
      January 3, 2006








Acknowledged
      and Agreed to by:





*The
      Company:*





**DSL.net,
      Inc.**








By: */s/
      David F. Struwas*


Name:
      David F. Struwas


Title:
      President and Chief Executive Officer


Date:
      January 3, 2006




























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