<PAGE>

                                                                    Exhibit 10.6
                                 FIRST AMENDMENT
                                TO LOAN DOCUMENTS


         THIS FIRST  AMENDMENT TO LOAN DOCUMENTS  (this  "Amendment") is entered
into as of March 31, 2000 among PF.NET CORP. (the "Borrower"),  PF.NET HOLDINGS,
LIMITED (the  "Parent") and the  Subsidiaries  of the Borrower  (individually  a
"Guarantor" and collectively the "Guarantors"; the Guarantors, together with the
Borrower,  individually  a "Loan Party" and  collectively  the "Loan  Parties"),
FIRST UNION NATIONAL BANK, as Administrative Agent (the "Administrative  Agent")
for the lenders party to the Credit Agreement defined below (the "Lenders"), the
Lenders  and STATE  STREET  BANK AND TRUST  COMPANY,  as  Corporate  Trustee and
PATRICK THEBADO,  as Individual  Trustee for the Secured Parties pursuant to the
Trust Agreement  defined below (the  "Trustees").  Capitalized terms used herein
and not otherwise  defined herein have the respective  meanings given to them in
the Credit Agreement and that certain Trust  Agreement,  dated as of October 29,
1999, among the Borrower and the Trustees (the "Trust Agreement").

                                    RECITALS

         WHEREAS,  the Borrower,  the  Administrative  Agent and the Lenders are
parties  to that  certain  Credit  Agreement  dated as of October  29,  1999 (as
amended, modified, supplemented or restated to date, the "Credit Agreement");

         WHEREAS,  in connection with the Credit  Agreement,  the parties hereto
have entered into various Loan Documents; and

         WHEREAS,  the  parties  to each of the  Loan  Documents  set  forth  on
Schedule 1 attached  hereto have agreed to amend each such Loan  Document on the
terms and subject to the conditions contained in this Amendment.

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

I.       AMENDMENTS TO LOAN DOCUMENTS

         1.1 Each of the Loan Documents set forth on Schedule 1 attached  hereto
are hereby  amended in their entirety to read in the form of such Loan Documents
attached to this Amendment.

         1.2  Each  of the  parties  hereto  acknowledge  that,  pursuant  to an
Assignment, Acceptance, Resignation and Appointment Agreement (the "Lucent/First
Union  Assignment  Agreement")  dated  as of  the  date  hereof  between  Lucent
Technologies  Inc.  ("Lucent")  and First Union  National Bank ("First  Union"),
Lucent has assigned, and First Union has assumed, all of


<PAGE>

Lucent's  obligations as a Lender,  Lucent has resigned as Administrative  Agent
and  Syndication  Agent  under  the Loan  Documents  and  First  Union  has been
appointed  as  the  successor   Administrative  Agent.  All  references  to  the
Administrative  Agent in each of the Loan Documents and all other  documents and
instruments  delivered in connection  therewith  are hereby  amended to refer to
First Union as Administrative  Agent. First Union will appoint a new Syndication
Agent at a later date.

II.      CONDITIONS PRECEDENT

         2.1 The  effectiveness of this Amendment is subject to the satisfaction
of each of the  following  conditions  precedent in a manner  acceptable  to the
Administrative Agent:

                  (a) The  Administrative  Agent shall have  received  copies of
         this  Amendment  duly executed by the Loan Parties,  the Trustees,  the
         Administrative Agent and the Lenders.

                  (b)      [Intentionally Omitted.]

                  (c) The  Administrative  Agent shall have received an executed
         promissory  note made by the Borrower and payable to the order of First
         Union in the principal amount of First Union's Commitments.

                  (d) The  Administrative  Agent shall have received an executed
         copy of the Lucent/First Union Assignment Agreement.

                  (e) First Union shall have  received the original  copy of the
         warrant  issued to Lucent by the Parent in connection  with the Closing
         and any assignment documentation requested by First Union in connection
         with the transfer of such warrant.

                  (f) The  Administrative  Agent shall have received a corporate
         organizational  chart  for the  Loan  Parties  and such  documents  and
         certificates as the Administrative  Agent or its counsel may reasonably
         request  relating to the  organization,  existence and good standing of
         the Loan Parties,  the  authorization  of this  Amendment and any other
         legal matters relating to the Loan Parties,  the Loan Documents or this
         Amendment.

                  (g) The Administrative Agent shall have received a letter from
         the Trustees addressed to the Administrative  Agent  acknowledging that
         the  Trustees  hold  in  their  possession  all  stock  and  membership
         certificates,  stock or transfer powers,  intercompany  notes and other
         instruments or chattel paper.

                  (h)      [Intentionally Omitted.]

                  (i)      [Intentionally Omitted.]

<PAGE>

                  (j) The Administrative Agent shall have received a letter from
         the  Trustees  to  Nations  Institutional   Reserves,   the  securities
         intermediary  under that certain  Securities Account Control Agreement,
         dated as of October 29, 1999, among the Borrower, Nations Institutional
         Reserves and the Trustees (the "Securities Account Control Agreement"),
         instructing Nations Institutional Reserves to direct all future notices
         thereunder to First Union instead of Lucent.

                  (k) The  Administrative  Agent shall have received an executed
         copy of (i) a Consent to Assignment executed by AT&T Corp., pursuant to
         which AT&T Corp.  consents  to the  assignment  by the  Borrower of its
         rights under the AT&T  Agreement to the  Collateral  Trustee and (ii) a
         Consent to  Assignment  executed by Lucent,  pursuant  to which  Lucent
         consents to the  assignment by the Borrower and PF. Net Supply Corp. of
         their rights under the Supply Agreement to the Collateral Trustee.

                  (l) The  Administrative  Agent  shall have  received  evidence
         satisfactory  to it that the insurance  required by Section 5.07 of the
         Credit Agreement is in effect and that the Administrative Agent and the
         Collateral  Trustee have been named as an  additional  insured and loss
         payee under all insurance policies to be maintained with respect to the
         properties of the Borrower constituting Collateral.

                  (m) The  Administrative  Agent shall have received an executed
         copy of the Fee Letter.

                  (n) The Administrative Agent shall have received an opinion of
         Latham & Watkins,  counsel  for the Loan  Parties  dated as of the date
         hereof and addressed to the  Administrative  Agent and the Lenders,  in
         form and substance satisfactory to the Administrative Agent.

                  (o) The  Administrative  Agent shall have received an executed
         copy of a waiver  letter from the  Trustees  and the  Required  Secured
         Parties (as  defined in the Trust  Agreement)  waiving the  requirement
         that a legal  opinion be delivered by the Borrower in  connection  with
         the amendments to the Trust  Agreement  pursuant to Section 1.1 hereof,
         in  form  and   substance   satisfactory   to  the   Trustees  and  the
         Administrative Agent.

                  (p) The Lenders  shall have received and approved the Business
         Plan and there  shall  have been no  material  adverse  changes  in the
         Business  Plan  compared to the  information  disclosed  to the Lenders
         prior to the date of execution of this Amendment.

                  (q) The  Lenders  shall  have  received  (i) copies of the all
         financial statements required to be delivered by the Borrower since the
         Effective  Date  pursuant  to the terms of  Section  5.01 of the Credit
         Agreement,  (ii) updated financial projections for the Borrower and its
         Subsidiaries  which take into account the Touch America Swap  Agreement
         and (iii) with  respect to the  Borrower  and the Parent,  an unaudited
         consolidated   balance  sheet  of  such  Person  and  its  consolidated
         subsidiaries as of January 31, 2000.

<PAGE>

                  (r) The Administrative Agent shall have received a certificate
         of the Borrower  dated as of October 29, 1999  attaching  copies of the
         Subscription  Agreement,  the Bridge  Loan  Agreement,  the Tax Sharing
         Agreement,   and  all  agreements  and  other  documents  delivered  in
         connection  therewith,  and  certifying,  as to each such agreement and
         document,  that (i) such copy is true and  correct and (ii) in the case
         of any such agreement, such agreement is in full force and effect.

                  (s) The Administrative Agent shall have received a certificate
         of the Borrower  dated as of October 29, 1999 to the effect that, as of
         the date  hereof,  (i) the AT&T  Agreement is in full force and effect,
         (ii) the Borrower is in  compliance  in all respects with the terms and
         conditions of the AT&T Agreement,  (iii) the Borrower has not taken any
         action which could result in the termination by AT&T for cause pursuant
         to Section 29.11 of the AT&T Agreement, and (iv) none of the parties to
         the  AT&T  Agreement  is in  default  under  or  with  respect  to  any
         obligation  thereunder  which default  could  reasonably be expected to
         have a Material Adverse Effect.

                  (t) The Administrative Agent shall have received evidence that
         the lenders party to the Bridge Loan  Agreement  have  consented to the
         terms and conditions of this Amendment.

                  (u) The Administrative Agent shall have received copies of all
         amendments, modifications or waivers to the Existing Agreements.

                  (v)  The  Administrative   Agent  and  First  Union  shall  be
         satisfied  that all fees and  other  amounts  due and  payable  to them
         hereunder, under the Fee Letter and in connection with the Lucent/First
         Union  Assignment  Agreement,   including,   to  the  extent  invoiced,
         reimbursement  or payment of all expenses  required to be reimbursed or
         paid by the Borrower  hereunder or under any other Loan Document,  have
         been paid or will be paid on the date hereof.

                  (w) All other  documents and legal matters in connection  with
         the  transactions  contemplated  by this Amendment  shall be reasonably
         satisfactory to the Administrative Agent and its counsel.

III.     MISCELLANEOUS

         3.1 The terms "Credit Agreement," "Trust Agreement,"  "Initial Security
Documents,"  "Initial  Guarantee" and "Indemnity and Contribution  Agreement" as
used in each of the  Loan  Documents  and any  other  documents  or  instruments
executed in connection  therewith  shall  hereafter  mean the Credit  Agreement,
Trust Agreement, Initial Security Documents, Initial Guarantee and Indemnity and
Contribution Agreement as amended by this Amendment.

<PAGE>

         3.2      Each of the Loan Parties represents and warrants as follows:

                  (a) It  has  taken  all  necessary  action  to  authorize  the
         execution, delivery and performance of this Amendment.

                  (b) This  Amendment  has been duly  executed and  delivered by
         such Loan Party and  constitutes  such Loan  Party's  legal,  valid and
         binding  obligations,  enforceable in accordance with its terms, except
         as such  enforceability  may be subject to (i) bankruptcy,  insolvency,
         reorganization,   fraudulent  conveyance  or  transfer,  moratorium  or
         similar laws  affecting  creditors'  rights  generally and (ii) general
         principles  of equity  (regardless  of whether such  enforceability  is
         considered in a proceeding at law or in equity).

                  (c) No  consent,  approval,  authorization  or  order  of,  or
         filing,  registration or qualification  with, any court or governmental
         authority or third party is required in connection  with the execution,
         delivery or performance by such Loan Party of this Amendment.

                  (d) No unwaived  event has  occurred and is  continuing  which
         constitutes a Default or an Event of Default under the Credit Agreement
         as amended by this Amendment.

         3.3 Each Loan Party hereby ratifies the Loan Document(s) to which it is
a party and acknowledges and reaffirms (a) that it is bound by all terms of such
Loan  Document(s)  (as  amended  hereby)  applicable  to it and  (b)  that it is
responsible   for  the  observance  and  full   performance  of  its  respective
Obligations under such Loan Document(s).

         3.4 The parties hereto  acknowledge and agree that this Amendment shall
constitute a Loan Document.

         3.5 This  Amendment  shall be binding  upon and inure to the benefit of
the parties hereto and their respective successors and assigns.

         3.6 Except as amended hereby,  the Credit Agreement and all other Loan
Documents shall continue in full force and effect.

         3.7 This Amendment may be executed in any number of counterparts, each
of which when so executed  and  delivered  shall be an  original,  but all of
which shall constitute one and the same  instrument.  Delivery of executed
counterparts  of this  Amendment  by  telecopy  shall  be  effective  as an
original  and  shall constitute a representation that an original shall be
delivered.

         3.8 Any  provision  of this  Amendment  held to be invalid,  illegal or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the  extent  of  such  invalidity,  illegality  or  unenforceability  without
affecting the validity,  legality and enforceability of the


<PAGE>

remaining  provisions hereof; and the invalidity of a particular  provision in a
particular  jurisdiction  shall  not  invalidate  such  provision  in any  other
jurisdiction.

         3.9 THIS  AMENDMENT  AND THE  RIGHTS  AND  OBLIGATIONS  OF THE  PARTIES
HEREUNDER  SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE  OF  NEW  YORK.   The  provisions  of  the  Credit   Agreement   regarding
jurisdiction,  venue,  service  of  process  and waiver of jury trial are hereby
incorporated by reference, mutatis mutandis.

<PAGE>

         IN WITNESS WHEREOF, each of the parties hereto has caused a counterpart
of this  Amendment to be duly  executed  and  delivered by their proper and duly
authorized officer as of the day and year first above written.


BORROWER:                  PF.NET CORP.


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Member of Executive Committee



<PAGE>

STATE OF NEW YORK  )
                   ) :ss:
COUNTY OF NEW YORK )

         On the 20th day of March 2000, before me personally came Stephen Irwin,
to me  personally  known and known to me to be the person  described  in and who
executed the  foregoing  instrument  as Member of Executive  Committee of PF.Net
Corp.,  who,  being by me duly sworn,  did depose and say that he resides at New
York City, that he is the Member of Executive  Committee of PF.Net Corp., one of
the corporations described in and which executed the foregoing instrument;  that
said  instrument  was signed on behalf of said  corporation by resolution of its
Board of Directors; that he signed his name thereto by like resolution; and that
he acknowledged said instrument to be the free act and deed of said corporation.




/s/  Helen May Posner
Helen May Posner
Notary Public State of New York
No. 41-5005666
Qualified in Queens County
Commission Expires Dec. 14 2000

<PAGE>

PARENT:                    PF.NET HOLDINGS, LIMITED


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Authorized Signatory

<PAGE>

GUARANTORS:                PF.NET SUPPLY CORP.


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Authorized Signatory

<PAGE>

                           PF.NET CONSTRUCTION CORP.


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Authorized Signatory

<PAGE>

                           PF.NET NETWORK SERVICES CORP.


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Authorized Signatory

<PAGE>

                           PF.NET PROPERTY CORP.


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Authorized Signatory

<PAGE>

                           PF.NET VIRGINIA, LLC


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Vice President




<PAGE>

                           PF.NET VIRGINIA CORP.


                           By:     /s/  Stephen Irwin
                           Name:   Stephen Irwin
                           Title:  Vice President

<PAGE>

TRUSTEES:                  STATE STREET BANK AND TRUST COMPANY,
                           not individually but solely as Corporate Trustee


                           By:     /s/  Patrick E, Thebado
                           Name:   Patrick E. Thebado
                           Title:  Assistant Vice President



                           /s/  Patrick Thebado
                           PATRICK THEBADO, as Individual Trustee

<PAGE>

STATE STREET BANK AND TRUST COMPANY

STATE OF   MA       )
                    ):ss:
COUNTY OF   Suffolk )

         On the 24th day of March,  2000,  before me personally  came Patrick E.
Thebado,  to me personally  known and known to me to be the person  described in
and who executed the foregoing  instrument as Assistant  Vice President of State
Street Bank and Trust Company, a Massachusetts  trust company, by me duly sworn,
did depose and say that he/she resides at Boston,  MA ; that he/she is Assistant
Vice  President  of State Street Bank and Trust  Company;  that he/she knows the
seal of said entity,  if any; that the seal affixed to said instrument,  if any,
is such  seal;  that said  instrument  was  signed  and sealed on behalf of said
entity in accordance  with its by-laws;  that he/she signed his/her name thereto
by like order; and that he/she  acknowledged  said instrument to be the free act
and deed of said entity.

[NOTARIAL SEAL]




Paul A. Preziosi
Notary Public
My Commission Expires November 24, 2006
/s/  Paul A. Preziosi

<PAGE>

INDIVIDUAL TRUSTEE

STATE OF   MA       )
                    ):ss:
COUNTY OF   Suffolk )

         On the 24th day of March,  2000,  before me personally  came Patrick E.
Thebado,  to me personally known who, being by me duly sworn, did depose and say
that he resides in Boston; and that said instrument is his free act and deed.

[NOTARIAL SEAL]



Paul A. Preziosi
Notary Public
My Commission Expires November 24, 2006
/s/  Paul A. Preziosi

<PAGE>

ADMINISTRATIVE
AGENT AND
LENDERS:                   FIRST UNION NATIONAL BANK,
                           individually in its capacity as a Lender
                           and in its capacity as Administrative Agent


                           By:     /s/  Magregor Hyde
                           Name:   Magregor G. Hyde
                           Title:  Director

<PAGE>

                                  Schedule 1 to
                                 First Amendment
                                To Loan Documents


         (a)      Credit Agreement;

         (b)      Trust Agreement;

         (c) Pledge Agreement  (Parent),  dated as of October 29, 1999,  entered
into by the Parent in favor of the Trustees;

         (d) Pledge Agreement (Borrower),  dated as of October 29, 1999, entered
into by the Borrower in favor of the Trustees;

         (e)  Pledge  Agreement  (Subsidiary),  dated as of  October  29,  1999,
entered into by PF.Net Network Services Corp. in favor of the Trustees;

         (f)  Security  Agreement  (Borrower),  dated as of  October  29,  1999,
entered into by the Borrower in favor of the Trustees;

         (g)  Security  Agreement  (Subsidiary),  dated as of October 29,  1999,
entered into by PF.Net Supply Corp. in favor of the Trustees;

          (h)  Security  Agreement  (Subsidiary),  dated as of October 29, 1999,
entered into by PF.Net Construction Corp. in favor of the Trustees;

          (i) Guarantee  and  Subordination  Agreement,  dated as of October 29,
1999, entered into by the Guarantors in favor of the Trustees;

         (j) Indemnity,  Subrogation  and  Contribution  Agreement,  dated as of
October 29, 1999, among the Loan Parties and the Collateral Trustee;

         (k) Patent Security  Agreement,  dated as of October 29, 1999,  entered
into by the Borrower in favor of the Trustees;

         (l) Patent Security  Agreement,  dated as of October 29, 1999,  entered
into by PF.Net Supply Corp. in favor of the Trustees;

         (m) Patent Security  Agreement,  dated as of October 29, 1999,  entered
into by PF.Net Construction Corp. in favor of the Trustees;

         (n) Copyright Security Agreement, dated as of October 29, 1999, entered
into by the Borrower in favor of the Trustees;

<PAGE>

         (o) Copyright Security Agreement, dated as of October 29, 1999, entered
into by PF.Net Supply Corp. in favor of the Trustees;

         (p) Copyright Security Agreement, dated as of October 29, 1999, entered
into by PF.Net Construction Corp. in favor of the Trustees;

         (q) Trademark Security Agreement, dated as of October 29, 1999, entered
into by the Borrower in favor of the Trustees;

         (r) Trademark Security Agreement, dated as of October 29, 1999, entered
into by PF.Net Supply Corp. in favor of the Trustees; and

         (s) Trademark Security Agreement, dated as of October 29, 1999, entered
into by PF.Net Construction Corp. in favor of the Trustees.