Exhibit 4.2


FORM OF RIGHT CERTIFICATE


(EXHIBIT B TO RIGHTS AGREEMENT)


	
  Certificate No. R-

  	
   

  	
          
  Rights

  



NOT EXERCISABLE AFTER AUGUST 7, 2009 OR EARLIER IF
REDEMPTION OR EXCHANGE OCCURS.  THE
RIGHTS ARE SUBJECT TO REDEMPTION AT $0.01 PER RIGHT AND TO EXCHANGE ON THE
TERMS SET FORTH IN THE RIGHTS AGREEMENT.


RIGHT CERTIFICATE

ABOVENET, INC.


This certifies
that                                        
or registered assigns, is the registered owner of the number of Rights set
forth above, each of which entitles the owner thereof, subject to the terms,
provisions and conditions of the Rights Agreement, dated as of August 3, 2006
(the “Rights Agreement”), between AboveNet, Inc., a Delaware corporation (the “Company”),
and American Stock Transfer & Trust Company (the “Rights Agent”), to
purchase from the Company at any time after the Distribution Date (as such term
is defined in the Rights Agreement) and prior to 5:00 pm, New York City time,
on August 7, 2009 at the office of the Rights Agent designated for such
purpose, or at the office of its successor as Rights Agent, one one-hundredth
of a fully paid non-assessable share of the Company’s Series A Junior
Participating Preferred Stock, par value $0.01 per share (the “Preferred Shares”),
at a purchase price of $100.00 per one one-hundredth of a Preferred Share (the “Purchase
Price”), upon presentation and surrender of this Right Certificate with the
Form of Election to Purchase duly executed. 
The number of Rights evidenced by this Right Certificate (and the number
of one one-hundredths of a Preferred Share which may be purchased upon exercise
hereof) set forth above, and the Purchase Price set forth above, are the number
and Purchase Price as of August 7, 2006 based on the Preferred Shares as
constituted at such date.


From and after the
time any Person becomes an Acquiring Person (as such terms are defined in the
Rights Agreement), if the Rights evidenced by this Right Certificate are
beneficially owned by (i) an Acquiring Person or an Affiliate or Associate
of any such Acquiring Person (as such terms are defined in the Rights
Agreement), (ii) a transferee of any such Acquiring Person, Associate or
Affiliate who becomes a transferee after the Acquiring Person becomes such, or
(iii) under certain circumstances specified in the Rights Agreement, a
transferee of any such Acquiring Person, Associate or Affiliate who becomes a
transferee prior to or concurrently with the Acquiring Person becoming such,
such Rights shall become null and void without any further action and no holder
hereof shall have any right with respect to such Rights from and after the time
any Person becomes an Acquiring Person.


As provided in the
Rights Agreement, the Purchase Price and the number of one one-hundredths of a
Preferred Share which may be purchased upon the exercise of the Rights



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evidenced by this Right Certificate are subject to
modification and adjustment upon the happening of certain events.


This Right
Certificate is subject to all of the terms, provisions and conditions of the
Rights Agreement, as amended from time to time, which terms, provisions and
conditions are hereby incorporated herein by reference and made a part hereof
and to which Rights Agreement reference is hereby made for a full description
of the rights, limitations of rights, obligations, duties and immunities
hereunder of the Rights Agent, the Company and the holders of the Right
Certificates.  Copies of the Rights
Agreement are on file at the Company’s principal executive offices and at the
Rights Agent’s offices located at 6201 Fifteenth Avenue, Brooklyn, NY 11219.


This Right
Certificate, with or without other Right Certificates, upon surrender at the
office of the Rights Agent designated for such purpose, may be exchanged for
another Right Certificate or Right Certificates of like tenor and date
evidencing Rights entitling the holder to purchase a like aggregate number of
Preferred Shares as the Rights evidenced by the Right Certificate or Right
Certificates surrendered shall have entitled such holder to purchase.  If this Right Certificate shall be exercised
in part, the holder shall be entitled to receive upon surrender hereof another
Right Certificate or Right Certificates for the number of whole Rights not
exercised.


Subject to the
provisions of the Rights Agreement, the Rights evidenced by this Certificate
(i) may be redeemed by the Company at a redemption price of $0.01 per Right or
(ii) may be exchanged in whole or in part for shares of the Company’s Common
Stock, par value $0.01 per share, or, upon circumstances set forth in the
Rights Agreement, cash, property or other securities of the Company, including
fractions of a share of Preferred Stock.


No fractional
Preferred Shares will be issued upon the exercise of any Right or Rights
evidenced hereby (other than fractions which are integral multiples of one
one-hundredth of a Preferred Share, which may, at the Company’s election, be
evidenced by depositary receipts) but in lieu thereof a cash payment will be
made, as provided in the Rights Agreement.


No holder of this
Right Certificate shall be entitled to vote or receive dividends or be deemed
for any purpose the holder of the Preferred Shares or of any other securities
of the Company which may at any time be issuable on the exercise hereof, nor
shall anything contained in the Rights Agreement or herein be construed to
confer upon the holder hereof, as such, any of the rights of a stockholder of
the Company or any right to vote for the election of directors or upon any
matter submitted to stockholders at any meeting thereof, or to give or withhold
consent to any corporate action, or to receive notice of meetings or other
actions affecting stockholders (except as provided in the Rights Agreement), or
to receive dividends or subscription rights, or otherwise, until the Right or
Rights evidenced by this Right Certificate shall have been exercised as
provided in the Rights Agreement.


This Right
Certificate shall not be valid or obligatory for any purpose until it shall
have been countersigned by the Rights Agent.



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WITNESS the facsimile signature of the
proper officers of the Company. Dated as of                   ,
            .


	
  ATTEST:

  	
   

  	
  ABOVENET, INC.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  Name:

  	
   

  	
  Name:

  
	
  Title:

  	
   

  	
  Title:

  
	
   

  	
   

  	
   

  
	
  COUNTERSIGNED:

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  AMERICAN
  STOCK TRANSFER & TRUST COMPANY, as Rights Agent

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
   

  	
   

  	
   

  
	
   

  	
  Authorized
  Signatory

  	
   

  
	
   

  	
  Name:

  	
   

  	
   

  	
   

  
	
   

  	
  Title:

  	
   

  	
   

  	
   

  
						



 



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FORM OF ASSIGNMENT


(To be executed by the registered holder if such

holder desires to transfer the Right Certificate.)


FOR VALUE RECEIVED
                                                                                    
hereby sells, assigns and transfers unto                                                                                                                                                                                                                                                                                                                                                                                                                   


(Please print name and address of transferee)


                                                                                                                                                                        
this Right Certificate, together with all right, title and interest therein,
and does hereby irrevocably constitute and appoint                                                                    
Attorney, to transfer the within Right Certificate on the books of the within-named
Company, with full power of substitution.


	
  Dated:

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  Signature

  



Signature
Guaranteed:


SIGNATURES must be
guaranteed by an “eligible guarantor institution” as defined in Rule 17Ad-15
promulgated under the Securities Exchange Act of 1934, as amended.


The undersigned
hereby certifies that (1) the Rights evidenced by this Right Certificate
are not being sold, assigned or transferred by or on behalf of a Person who is
or was an Acquiring Person, an Interested Stockholder or an Affiliate or
Associate thereof (as such terms are defined in the Rights Agreement); and
(2) after due inquiry and to the best of the knowledge of the undersigned,
the undersigned did not acquire the Rights evidenced by this Right Certificate
from any Person who is or was an Acquiring Person, an Interested Stockholder,
or an Affiliate or Associate thereof.


	
  

  	
  Signature

  



 



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FORM OF ELECTION TO PURCHASE


(To
be executed if holder desires to exercise

Rights represented by the Right Certificate.)


To AboveNet, Inc.:


The undersigned
hereby irrevocably elects to exercise                                                                 
Rights represented by this Right Certificate to purchase the Preferred Shares
issuable upon the exercise of such Rights and requests that certificates for
such Preferred Shares be issued in the name of:


Please insert social security

or other identifying number:                                   


                                                                                                                                                                                                         


(Please print name and address)


                                                                                                                                                                                                         


If such number of Rights shall not be all the Rights
evidenced by this Right Certificate, a new Right Certificate for the balance
remaining of such Rights shall be registered in the name of and delivered to:


Please insert social security

or other identifying number:                                   


                                                                                                                                                                                                         


(Please print name and address)


                                                                                                                                                                                                         


	
  Dated:

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  Signature

  



 



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Signature Guaranteed:


Signatures must be
guaranteed by an “eligible guarantor institution” as defined in Rule 17Ad-15
promulgated under the Securities Exchange Act of 1934, as amended.


The undersigned
hereby certifies that (1) the Rights evidenced by this Right Certificate are
not beneficially owned by nor are they being exercised on behalf of an
Acquiring Person, an Interested Stockholder or an Affiliate or Associate
thereof (as such terms are defined in the Rights Agreement); and (2) after
due inquiry and to the best of the knowledge of the undersigned, the
undersigned did not acquire the Rights evidenced by this Right Certificate from
any Person who is or was an Acquiring Person, an Interested Stockholder, or an
Affiliate or Associate thereof.


	
  

  	
  Signature

  



NOTICE


The signature in
the Form of Assignment or Form of Election to Purchase, as the case may be,
must conform to the name as written upon the face of this Right Certificate in
every particular, without alteration or enlargement or any change whatsoever.


In the event the
certification set forth above in the Form of Assignment or the Form of Election
to Purchase, as the case may be, is not completed, the Company and the Rights
Agent will deem the beneficial owner of the Rights evidenced by this Right
Certificate to be an Acquiring Person or an Affiliate or Associate thereof (as
defined in the Rights Agreement) and such Assignment or Election to Purchase
will not be honored.



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