##### 



Exhibit 10.5.3
  AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT
    
    
    1. CONTRACT ID CODE
    
    
    Page1 of 12. Amendment/Modification No.
    
    
    3. Effective Date
    
    
    4. Requisition/Purchase Req. No.
    
    
    5. Project No. (If applicable)0017
    
    
    Aug 24, 2006
    
    
    NT1A911-6-0279ML6. Issued By                                              Code
    
    
    
    F6001201
    
    
    
    7. Administered By (If other than Item 6)
    
    
    CodeDOC/NOAA/AGO
    
    
    
    
    
    
    
    SEE BLOCK 6STAFF OFFICE & EXTERNAL CLIENTS, AD1305 EAST WEST HIGHWAY, RM 7601SILVER SPRING, MD 20910DIANE R. TRICE 301-713-0838 X 102
 8. Name and Address of Contractor (No., Street, County and Zip Code)
    
    
    (X)
    
    
    9A. Amendment of Solicitation No.NEUSTAR, INC.
    
    
    
    
    Vendor ID 00000190
    
    
    
    
    
    9B. Date (See Item 11)46000 CENTER OAK PLAZASTERLING, VA 20166
    
    
    
    
    DUNS: 112403295
    
    
    X
    
    
    10A. Modification of Contract/Order No.SB1335-02-W-0175CAGE: 3DXC3
    
    
    
    
    
    10B. Date (See Item 13)
Oct. 26, 2001Code
    
    
    Facility Code11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS
 o
    
    The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offers o is extended, o is not extended.Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended, by one of the following methods:(a) By completing Items 8 and 15,
and returning ___ copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted; or (c) By separate letter or telegram which includes a reference to the
solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment
you desire to change an offer already submitted, such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date
specified.
 12. Accounting and Appropriation Data (If required)          $ US          0.0013. THIS ITEM ONLY
APPLIES TO MODIFICATIONS OF CONTRACT/ORDERS.IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.
 (X)
    
    A.

This
change order is issued pursuant to: (Specify authority) The changes set forth in Item 14 are made in the Contract Order No. in Item 10A.B.

The
above numbered Contract/Order is modified to reflect the
administrative changes (such as changes in paying office,
appropriation date, etc.) Set fourth Item 14, pursuant to the authority of FAR 43.103(b)X
    
    C.
    This supplemental agreement is entered into pursuant to authority of:FAR 52.243-1 Changes, and Mutual Agreement of the PartiesD.
    Other (Specify type of modification and authority)
 x o
 
 Organized by UCF section headings, including solicitation/contract subject matter where feasible
        15A. Name and Title of
Signer (Type or Print)
    
    
    
    16A.
    Name and title
of Contracting Officer (Type or Print)Steven Boyce, VP & Controller
    
    
    
    
    CATHERINE E. HOLLAND
    
    
    301-713-0838 X139Contracting Officercatherine.holland@noaa.gov15B. Contractor/Offeror
    
    
    15C. Date Signed
    
    
    16B.
    
    United States of America
    
    
    
    
    16C. Date Signed/s/ Steven Boyce
    
    
    Aug. 25, 2006
    
    
    /s/ Catherine E. Holland
    
    
    
    
    August 24, 2006(Signature of person authorized to sign)
    
    
    
    
    
    (Signature of Contracting Officer)
 NSN 7640-01-152-8070
PREVIOUS EDITIONS UNUSABLE
    
    30-105
    
    STANDARD FORM 30 (REV. 10-83)
Prescribed by GSA FAR (48 CFR) 53.243




---



##### 



AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT
    
    
    1. CONTRACT ID CODE
    
    
    Page1 of 12. AMENDMENT/MODIFICATION NO.
    
    
    3. EFFECTIVE DATE
    
    
    4. REQUISITION/PURCHASE REQ. NO.
    
    
    5. PROJECT NO. (If applicable)0018
    
    
    

    Oct 20, 2006
    
    
    

NTIA911-7-029IML6. ISSUED BY                               CODE
    
    
    F6001201
    
    
    
    7. ADMINISTERED BY (If other
than Item 6)    SEE BLOCK 6
    
    
    CODEDOC/NOAA/AGOSTAFF OFFICE
& EXTERNAL CLIENTS, AD1305 EAST WEST HIGHWAY, RM 7601SILVER
SPRING, MD 20910DIANE R. TRICE 301-713-0838 x102
 118. NAME AND ADDRESS OF CONTRACTOR (No., street, county, and Zip Code)
    
    (X)
    
    
    9A. AMENDMENT OF SOLICITATION NO.NEUSTAR, INC.
    
    
    Vendor ID: 00000190
    
    
    
    
    
    9B. DATE (SEE ITEM 11)46000
CENTER OAK PLAZASTERLING, VA 201666593
    
    
    DUNS: 112403295
    
    
    
    
    
    10A. MODIFICATION OF CONTRACT/ORDER
NO. SB1335-02-W-0175CAGE: 3DXC3
    
    
    (X)
    
    
    10B. DATE (SEE ITEM 13)Oct 26, 2001CODE*
    
    
    FACILITY CODE11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS
 c
    
    The above numbered solicitation is amended as set forth in Item 14.
The hour and date specified for receipt of Offers c is
extended, c is not extended.Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended, by one of the following methods:(a) By completing Items 8 and 15,
and returning ___ copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted; or (c) By separate letter or telegram which includes a reference to the
solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment
you desire to change an offer already submitted, such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date
specified.
 12. ACCOUNTING AND APPROPRIATION DATA (If required)6107911001100008000000000000000000000000025220000000000 $ US       0.0013. THIS ITEM  APPLIES ONLY TO MODIFICATIONS OF CONTRACT/ORDERS.IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.
 (X)A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT ORDER NO. IN ITEM 10A.B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation date, etc.) SET FOURTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(b).C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:X
    
    
    D. OTHER (Specify type of modification and authority)FAR 52217-9 Option to Extend the Term of the Contract
 E. IMPORTANT: Contractor x is not, o is required to sign this document and return     copies to the issuing office.14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)
  
 Except as provided herein, all terms and conditions of the document referenced in Item 9A or 10A, as heretofore changed, remains unchanged and in full force and effect.15A.
    
    
    NAME AND TITLE OF SIGNER (Type or print)
    
    
    
    
    
    16A.
    
    NAME AND TITLE OF CONTRACTING OFFICER (Type of print)GARY RICE
    
    
    301-713-0838 x190Contracting Officergary.rice@noaa.gov15B.
    
    
    CONTRACTOR/OFFEROR
    
    
    15C. DATE SIGNED
    
    
    16B.
    
    United States of America
    
    
    16C. DATE SIGNED Oct 20, 2006(Signature of person authorized to sign)
    
    
    
    
    
    BY
    
    /s/ Gary Rice(Signature of Contracting Officer)
 NSN 7540-01-152-8070
    
    30-105
    STANDARD FORM 30 (REV. 10-83)PREVIOUS EDITIONS
    
    
    Prescribed by GSA FAR (48 CFR)UNUSABLE
    
    
    53.243