Exhibit 24



                                   POWER OF ATTORNEY

        KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and
appoints each of Karen M. King and Alan K. Austin, signing singly, the
undersigned's true and lawful attorney-in-fact to:

        (1)    execute for and on behalf of the undersigned, in the
               undersigned's capacity as a director of NetScout Systems, Inc.
               (the "COMPANY"), Forms 3, 4, and 5 in accordance with Section
               16(a) of the Securities Exchange Act of 1934 and the rules
               thereunder, and any other forms or reports the undersigned may be
               required to file in connection with the undersigned's ownership,
               acquisition, or disposition of securities of the Company;

        (2)    do and perform any and all acts for and on behalf of the
               undersigned that may be necessary or desirable to complete and
               execute any such Form 3, 4, or 5, or other form or report, and
               timely file such form or report with the United States Securities
               and Exchange Commission and any stock exchange or similar
               authority; and

        (3)    take any other action of any type whatsoever in connection with
               the foregoing that, in the opinion of such attorney-in-fact, may
               be of benefit to, in the best interest of, or legally required
               by, the undersigned, it being understood that the documents
               executed by such attorney-in-fact on behalf of the undersigned
               pursuant to this Power of Attorney shall be in such form and
               shall contain such terms and conditions as such attorney-in-fact
               may approve in such attorney-in-fact's discretion.

        The undersigned hereby grants to each such attorney-in-fact full power
with authority to do and perform any and every act and thing whatsoever
requisite, necessary, or proper to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this Power of Attorney and the
rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934.

        This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 8th day of November, 2007.


                                                          /s/ Kenneth Y. Hao
                                                      --------------------------
                                                          Kenneth Y. Hao