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                                                                   EXHIBIT 10.12
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                            MASTER LEASE AGREEMENT
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                                                                        No. 1789
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This Master Lease Agreement (the "MLA") is entered into by and between
TECHNOLOGY Credit Corporation ("Lessor"), having its principal place of business
at 1650 Zanker Road, Suite 236, San Jose, California 95112, and PSINet, Inc.
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("Lessee"), having its principal place of business at 510 Huntmar Park Drive,
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Herndon, VA 22070
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        1. LEASE AGREEMENT. Lessor agrees to lease to Lessee, and Lessee agrees
to lease from Lessor, the equipment (the "Equipment") referenced in each of the
schedules (the "Schedule" or "Schedules") which incorporate the MLA therein (the
"Lease").

        2. TERM. Each lease shall be effective upon the execution of the MLA and
the related Schedule by the Lessor and the lessee. The lease term (the "Lease
Term") of the Equipment referenced in each of the Schedules shall commence on
the rent commencement date specified in each Schedule (the "Rent Commencement
Date"). The Rent Commencement Date shall be the date upon which the Equipment is
delivered and determined to be ready for use at the Lessee's location as
referenced in a certificate pursuant to which Lessee unconditionally accepts the
Equipment subject to such Lease (the "Certificate of Installation"). Lessor
shall not be obligated, or bound by, any Lease until Lessee has provided to
Lessor a "Certificate of Installation" and has received the advance Rent
payment(s) required by such Lease.

        3. RENT. The rent (the "Rent") for the Equipment referenced in any
Schedule shall be as stated in such Schedule and shall be payable according to
the provisions of such Schedule. If any amount payable under a Schedule is not
received by Lessor within 10 days of the due date, Lessee agrees to pay an
Overdue Charge, as defined herein, with respect to such amount.

        4. SELECTION AN ASSIGNMENT. Lessee will select the type, quantity and
Supplier of each item of Equipment designated in a Schedule, and Lessee hereby
assigns to Lessor all of its right, title and interest in and to the related
equipment purchase agreement, a copy of which has been provided to Lessor by
Lessee (the "Agreement"). The Agreement may be amended with the consent of
Lessor. Any such assignment with respect to Equipment shall become binding upon
Lessor when Lessor and Lessee have entered into a Lease with respect to such
Equipment and Lessor has received a related Certificate of Installation. Upon
such an assignment becoming effective, Lessor shall be obligated to purchase the
Equipment from the Supplier in accordance with the provisions of the Agreement.
It is expressly agreed that Lessee shall at all times remain liable to Supplier
under the Agreement to perform all the duties and obligations of Lessee
thereunder, except for the obligation to purchase the Equipment to the extent
expressly assumed by the Lessor hereunder, and that the Lessee shall be entitled
to the same rights of the purchaser of the Equipment under the Agreement, except
such rights of the purchaser of the Equipment under the Agreement except such
right, title and interest in the Equipment retained exclusively by the Lessor as
owner of the Equipment. Lessor shall have no liability for a Supplier's failure
to meet the terms and conditions of the Agreement.

        5. DELIVERY AND INSTALLATION. Lessee shall be responsible for payment of
all transportation, packing, installation, testing and other charges associated
with the delivery, installation or use of any Equipment which are not included
in the Agreement with respect to such Equipment.

        6. WARRANTIES. LESSOR MAKES NO REPRESENTATION OR WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, WITH RESPECT TO ANY OF THE EQUIPMENT, ITS MERCHANTABILITY OR
ITS FITNESS FOR A PARTICULAR PURPOSE. LESSOR SHALL NOT BE LIABLE TO LESSEE OR
ANY OTHER PERSON FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL
DAMAGES ARISING FORM LESSEE'S USE OF THE EQUIPMENT, OR FOR DAMAGES BASED ON
STRICT OR ABSOLUTE TORT LIABILITY OR LESSOR'S PASSIVE NEGLIGENCE. LESSEE HEREBY
ACKNOWLEDGES THAT ANY MANUFACTURER'S OR SUPPLIER'S WARRANTIES WITH RESPECT TO
THE EQUIPMENT ARE FOR THE BENEFIT OF BOTH LESSOR AND LESSEE. NOTWITHSTANDING THE
FOREGOING, LESSEE'S OBLIGATIONS TO PAY EACH RENT PAYMENT DUE, OR OTHERWISE
PERFORM ITS OBLIGATIONS, UNDER THIS LEASE ARE ABSOLUTE AND UNCONDITIONAL.

        7. TITLE TO AND LOCATION OF EQUIPMENT. Lessor shall retain title to each
item of Equipment. Lessee, at its expense, shall protect Lessor's title and keep
the Equipment free from all claims, liens, encumbrances and legal processes. The
Equipment is personal property and is not to be regarded as part of the real
estate on which it may be situated. If requested by Lessor, Lessee will, at
Lessee's expense, furnish a landlord or mortgagee waiver with respect to the
Equipment. The Equipment shall not be removed from the location specified in the
Schedule without the written consent of Lessor. Lessee shall, upon Lessor's
request, affix and maintain plates, tags or other identifying labels, showing
Lessor's ownership of the Equipment in a prominent position on the Equipment.

        8. USE OF EQUIPMENT, INSPECTION AND REPORTS. The use of the Equipment by
Lessee shall conform with all applicable laws, insurance policies, and
warranties of the manufacturer or Supplier of the Equipment. Lessor shall have
the right to inspect the Equipment at the premises where the Equipment is
located. Lessee shall notify the Lessor promptly of any claims, items,
encumbrances or legal processes with respect to the Equipment.

        9. FURTHER ASSURANCES. Lessee shall execute and deliver to Lessor such
instruments as Lessor deems necessary for the confirmation of this Lease and
Lessor's rights hereunder. Lessor is authorized to file financing statements
signed only by the Lessor in accordance with the Uniform Commercial Code, or
financing statements signed by Lessor as Lessee's attorney-in-fact. Any such
filing with respect to the Equipment leased pursuant to a true lease shall not
be deemed evidence of any intent to create a security interest under the Uniform
Commercial Code.

        10. MAINTENANCE AND REPAIRS. Lessee shall, at its expense, maintain each
item of Equipment in good condition, normal wear and tear excepted. Lessee shall
not make any addition, alteration, or attachment to the Equipment without
Lessor's prior written consent. Lessee shall make no repair, addition,
alteration or attachment to the Equipment which interferes with the normal
operation or maintenance thereof, creates a safety hazard, or might result in
the creation of a mechanic's or materialman's lien.

        11. LESSOR'S PERFORMANCE OF LESSEE'S OBLIGATIONS. If Lessee fails to
perform any of its obligations under a Lease, Lessor may perform any act or make
any payment which Lessor deems necessary for the maintenance and preservation of
the Equipment subject thereto and Lessor's title thereto. All sums so paid by
Lessor (together with all related Overdue Charges), and reasonable attorneys'
fees incurred by Lessor in connection therewith, shall be additional rent
payable to Lessor on demand. The performance of any such act or the making of
any such payment by Lessor shall not be deemed a waiver or release of any
obligation or default on the part of Lessee.

        12. INDEMNIFICATION. Lessee assumes liability for, and hereby agrees to
indemnify, protect and hold harmless, Lessor, and its agents, employees,
officers, directors, partners and successors and assigns, from and against, all
liabilities, obligations, losses, damages, injuries, claims, demands, penalties,
actions, costs and expenses, including, without limitation, reasonable
attorneys' fees, of whatever kind and nature, in contract or in tort, arising
out of the use, condition, operation, ownership, selection, delivery, leasing or
return of any item of Equipment, regardless of when, how and by whom operated,
or any failure on the part of Lessee to perform or comply with any of its
obligations under a Lease, excluding, however, any of the foregoing which result
from the gross negligence or willful misconduct of Lessor. Such indemnities and
assumptions of liabilities and obligations shall continue in full force and
effect, notwithstanding the expiration or other termination of such Lease.
Nothing contained in any Lease shall authorize Lessee to operate the Equipment
subject thereto so as to incur or impose any liability on, or obligation for or
on behalf of, Lessor.

        13. NO OFF-SET. All Rent shall be paid by Lessee irrespective of any 
off-set, counterclaim, recoupment, defense or other right which Lessee may have
against Lessor, the manufacturer or Supplier of the Equipment or any other
party.

        14. ASSIGNMENT BY LESSEE. Lessee shall not, without Lessor's prior
written consent, (a) sell, assign, transfer, pledge, hypothecate, or otherwise
dispose of, encumber or suffer to exist a lien upon or against, any of the
Equipment or any Lease or any interest therein, by operation of law or
otherwise, or (b) sublease or lend any of the Equipment or permit any of the
Equipment to be used by anyone other than Lessee.

        15. ASSIGNMENT BY LESSOR. Lessor may assign, sell or encumber its
interest in any of the Equipment and any Lease. Upon Lessor's written request,
Lessee shall pay directly to the assignee of any such interest all Rent and
other sums due under an assigned Lease. THE RIGHTS OF ANY SUCH ASSIGNEE SHALL
NOT BE SUBJECT TO ANY ABATEMENT, DEDUCTION, OFF-SET, COUNTERCLAIM, RECOUPMENT,
DEFENSE OR OTHER RIGHT WHICH LESSEE MAY HAVE AGAINST LESSOR OR ANY OTHER
PERSON OR ENTITY. Notwithstanding the foregoing, any such assignment (a) shall
be subject to Lessee's right to possess and use the Equipment subject to a Lease
so long as Lessee is not in default thereunder, and (b) shall not release any of
Lessor's obligations hereunder.

        16. RETURN OF EQUIPMENT. Unless Lessee has exercised its option, if any,
to renew a lease or purchase the Equipment subject thereto, upon expiration of
the then current Lease Term of such Lease, Lessee shall, at its expense, cause
such Equipment to be removed, disassembled, and placed in the same condition as
when delivered to Lessee (reasonable wear and tear excepted) and properly crate
such Equipment for shipment and deliver it to a common carrier designated by
Lessor. Lessee will ship such Equipment, F.O.B. destination, to any address
specified in writing by Lessor within the continental United States. All
additions, attachments, alterations and repairs made or placed upon any of the
Equipment shall become part of such Equipment and shall be the property of
Lessor.

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        17. EVENTS OF DEFAULT. The occurrence of any of the following shall be 
deemed to constitute an Event of Default hereunder: (a) Lessee fails to pay
Rent, any other amount it is obligated to pay under a Lease or any other amount
it is obligated to pay to Lessor and does not cure such failure within 10 days
of such amount becoming due; (b) Lessee fails to perform or observe any
obligation or covenant to be performed or observed by Lessee hereunder or under
any Schedule, including, without limitation, supplying all requested
documentation, and does not cure such failure within 10 days of receiving
written notice thereof from Lessor; (c) any warranty, representation or
statement made or furnished to Lessor by or on behalf of Lessee is proven to
have been false in any material respect when made or furnished; (d) the
attempted sale or encumbrance by Lessee of the Equipment, or the making of any
levy, seizure or attachment thereof or thereon; or (e) the dissolution,
termination of existence, discontinuance of business, insolvency, or appointment
of a receiver of any part of the property of Lessee, assignment by Lessee for
the benefit of its creditors, the commencement of proceedings under any
bankruptcy, reorganization or arrangement laws by or against Lessee, or any
other act of bankruptcy on the part of Lessee.

        18. REMEDIES OF LESSOR. At any time after occurrence of any Event of
Default, Lessor may exercise one or more of the following remedies: (a) Lessor
may terminate any or all of the Leases with respect to any or all items of
Equipment subject thereto: (b) Lessor may recover from Lessee all Rent and other
amounts then due and to become due under any or all of the Leases; (c) Lessor
may take possession of any or all items of Equipment, wherever the same may be
located, without demand or notice, without any court order or other-process of
law and without liability to Lessee for any damages occasioned by such taking of
possession, and any such taking of possession shall not constitute a termination
of any Lease; (d) Lessor may demand that Lessee return any or all items of
Equipment to Lessor in accordance with Paragraph 16; and (e) Lessor may pursue
any other remedy available at law or in equity, including, without limitation,
seeking damages, specific performance or an injunction.

        Upon repossession or return of any item of the Equipment, Lessor shall 
sell, lease or otherwise dispose of such item in a commercially reasonable 
manner, with or without notice and on public or private bid, and apply the net 
proceeds thereof (after deducting the estimated fair market value of such item 
at the expiration of the term of the applicable Lease, in the case of sale, or 
the rents due for any period beyond the scheduled expiration of such Lease, in 
the case of any subsequent lease of such item, and all expenses, including 
without limitation, reasonable attorneys' fees, incurred in connection 
therewith) towards the Rent and other amounts due under such Lease, with any 
excess net proceeds to be retained by Lessor.

        Each of the remedies under this Lease shall be cumulative, and not 
exclusive, and in addition to any other remedy referred to herein or otherwise 
available to Lessor in law or in equity. Any repossession or subsequent sale or 
lease by Lessor of any item of Equipment shall not bar an action for a 
deficiency as herein provided, and the bringing of an action or the entry of 
judgement against Lessee shall not bar Lessor's right to repossess any or all 
items of Equipment.

        19. CREDIT AND FINANCIAL INFORMATION. Within 90 days of the close of 
each of Lessee's fiscal years, Lessee shall deliver to Lessor a copy of Lessee's
annual report, if any, and an audited balance sheet and profit and loss 
statement with respect to such year. If audited financial statements of Lessee 
for such year are not prepared, Lessee may provide financial statements 
certified by an officer of Lessee. At Lessor's request, Lessee shall deliver to 
Lessor a balance sheet and profit and loss statement for any of its fiscal 
quarters, certified by an officer of Lessee.

        20. INSURANCE. Lessee shall obtain and maintain for the entire Lease
Term of each Lease (and any renewal or extension thereof), at its own expense,
property damage and personal liability insurance and insurance against loss or
damage to the Equipment, including, without limitation, loss by fire (with
extended coverage), theft and such other risks of loss as are customarily
insured against with respect to the types of Equipment leased hereunder and by
the types of businesses in which such Equipment will be used by Lessee. Such
insurance shall be in such amounts, with such deductibles, in such form and with
such insurers as shall be satisfactory to Lessor; provided, however, that the
amount of the insurance against loss or damage to the Equipment shall not be
less than the greater of the replacement value of the Equipment, from time to
time, or the original purchase price of the Equipment. Each insurance policy
shall name Lessee as an insured and Lessor as an additional insured or loss
payee, and shall contain a clause requiring the insurer to give Lessor at least
30 days prior written notice of any alteration in the terms of such policy or of
the cancellation thereof. Lessee shall furnish to Lessor a certificate of
insurance or other evidence satisfactory to Lessor that such insurance coverage
is in effect; provided, however, that Lessor shall be under no duty either to
ascertain the existence of or to examine such insurance policy or to advise
Lessee in the event such insurance coverage shall not comply with the
requirements hereof. Lessee shall give Lessor prompt notice of any damage to, or
loss of, any of the Equipment, or any part thereof, or any personal injury or
property damage occasioned by the use of any of the Equipment.

        21. TAXES. Lessee hereby assumes liability for, and shall pay when due, 
and, on a net after-tax basis, shall indemnify, protect and hold harmless Lessor
against all fees, taxes and governmental charges (including, without limitation,
interest and penalties) of any nature imposed on or in any way relating to 
Lessor, Lessee, any item of Equipment or any Lease, except state and local taxes
on or measured by Lessor's net income (other than any such tax which is in 
substitution for or relieves Lessee from the payment of taxes it would otherwise
be obligated to pay or reimburse to Lessor as herein provided) and federal taxes
on Lessor's net income. Lessee shall, at its expense, file when due with the 
appropriate authorities any and all tax and similar returns, and reports 
required to be filed with respect thereto, for which it has indemnified Lessor 
hereunder or, if requested by Lessor, notify Lessor of all such requirements and
furnish Lessor with all information required for Lessor to effect such filings. 
Any fees, taxes or other charges paid by Lessor upon failure of Lessee to make 
such payments shall, at Lessor's option, become immediately due from Lessee and 
shall be subject to the Overdue Charge from the date paid by Lessor until the 
date reimbursed by Lessee.

        22. SEVERABILITY. If any provision of any Lease is held to be invalid by
a court of competent jurisdiction, such invalidity shall not affect the other 
provisions of such Lease or any provision of any other Lease.

        23. NOTICES. All notices hereunder shall be in writing and shall be 
deemed given when sent by certified mail, postage prepaid, return receipt 
requested, addressed to the party to which it is being sent at its address set 
forth herein or to such other address as such party may designate in writing to 
the other party.

        24. AMENDMENTS, WAIVERS AND EXTENSIONS. This MLA and each Schedule 
constitute the entire agreement between Lessor and Lessee with respect to the 
lease of the Equipment subject to such Schedule, and supersede all previous 
communications, understandings, and agreements, whether oral or written, between
the parties with respect to such subject matter. No provision of any Lease may 
be changed, waived, amended or terminated except by a written agreement, 
specifying such change, waiver, amendment or termination, signed by both Lessee 
and Lessor, except that Lessor may insert, on the appropriate schedule, the 
serial number of Equipment, after delivery of such Equipment, and the 
Installation Date for the Equipment, after receiving a Certificate of
Installation with respect thereto. No waiver by Lessor of any Event of Default
shall be construed as a waiver of any future Event of Default or any other Event
of Default. At the expiration of the Lease Term with respect to a Lease, upon
notice given by Lessee at lest ninety (90) days prior thereto, (a) such Lease
shall be renewed or the Equipment subject thereto shall be purchased under the
terms and conditions set forth herein for a term and rent amount or purchase
price, as the case may be, to be agreed upon, or (b) if no such agreement is
reached prior to the expiration of such Lease Term or such notice specifies that
Lessee intends to return the Equipment, then Lessee shall return the Equipment
to Lessor in the manner prescribed in Paragraph 16 of this MLA. In the absence
of Lessor's timely receipt of the notice contemplated by the preceding sentence,
the Lease shall be automatically extended, on a month-to-month basis, until
terminated (upon notice by either party given at least ninety (90) days prior to
the end of the month on which the termination is to be effective) or until
renewed or the Equipment subject thereto is purchased by agreement of the
parties. Unless otherwise agreed, Lessee shall continue to pay the Rent for each
month following such Lease Term until the Equipment subject to such Lease is
returned pursuant to Paragraph 16 of this MLA.

        25. CONSTRUCTION. This MLA shall be governed by and construed in 
accordance with the internal laws, but not the choice of laws provisions, of the
State of California. The titles of the sections of this MLA are convenience only
and shall not define or limit any of the terms or provisions hereof. Time is of 
the essence in each of the provisions hereof.

        26. PARTIES. This MLA shall be binding upon, and inure to the benefit 
of, the permitted assigns, representatives and successors of the Lessor and 
Lessee. If there is more than one Lessee named in this MLA, the liability of 
each shall be joint and several.

        27. COUNTERPARTS. Each Lease may be executed in two or more 
counterparts, each of which shall be deemed an original and all of which 
together shall constitute but one and the same instrument.

        28. OVERDUE CHARGE. Overdue Charge shall mean an amount equal to 2% per 
month of any payment under a Lease which is past due, including, without 
limitation, any amounts not included in any payment of Rent hereunder, or the 
highest charge permitted by law, whichever is lower.

The person executing this MLA on behalf of Lessee hereby certifies that he or 
she has read, and is duly authorized to execute, this MLA.

Accepted By:

TECHNOLOGY Credit Corporation           LESSEE: PSINet, Inc.