EXHIBIT 20



                                 AMENDMENT NO. 1

                                     TO THE

                           SECOND AMENDED AND RESTATED

                       LIMITED LIABILITY COMPANY AGREEMENT

                                       OF

                           NET2PHONE HOLDINGS, L.L.C.


         This Amendment No. 1 to the Second Amended and Restated Limited
Liability Company Agreement of Net2Phone Holdings, L.L.C. (the "Company") is
made, entered into and effective as of October 31, 2001 (the "Agreement"), by
and among AT&T Corp., a New York corporation ("AT&T"), ITelTech, LLC, a Delaware
limited liability company ("AT&T Sub"), IDT Corporation, a Delaware corporation
("IDT Corporation"), IDT Domestic-Union, LLC, a Delaware limited liability
company ("IDT Sub"), IDT Investments Inc., a Nevada corporation ("IDT
Investments"), Liberty Media Corporation, a Delaware corporation ("LMC"), and
LMC Animal Planet, Inc., a Colorado corporation ("Liberty Sub"). Capitalized
terms used herein but not otherwise defined herein have the meanings ascribed to
such terms in the Second Amended and Restated Limited Liability Company
Agreement (as defined below).

         WHEREAS, the Company was formed under the Act pursuant to the
Certificate of Formation filed with the Secretary of State of the State of
Delaware on October 17, 2001;

         WHEREAS, IDT Sub entered into a Limited Liability Company Agreement,
dated as of October 19, 2001, in respect of the Company, which was amended and
restated on October 19, 2001, by the Amended and Restated Limited Liability
Company Agreement, dated as of October 19, 2001, entered into by IDT Sub, AT&T
Sub and AT&T, and which was further amended and restated on October 19, 2001 by
the Second Amended and Restated Limited Liability Company Agreement, dated as of
October 19, 2001 (the "Second Amended and Restated Limited Liability Company
Agreement"), entered into by AT&T, AT&T Sub, IDT Corporation, IDT Sub, IDT
Investments, LMC and Liberty Sub; and

         WHEREAS, AT&T, AT&T Sub, IDT Corporation, IDT Sub, IDT Investments, LMC
and Liberty Sub desire to amend Section 2.2 of the Second Amended and Restated
Limited Liability Company Agreement by changing the name of the Company to "NTOP
Holdings, L.L.C.", and file a Certificate of Amendment to the Certificate of
Formation of the Company to reflect such name change.



         NOW, THEREFORE, the parties hereby agree as follows:

         1. Amendment. The Second Amended and Restated Limited Liability Company
Agreement is hereby amended by deleting Section 2.2 in its entirety and
replacing it with the following:

         "Section 2.2. Company Name. The business of the Company shall be
conducted under the name of "NTOP Holdings, L.L.C." in the State of Delaware and
under such name or such assumed or trade names as the Board of Managers deem
necessary or appropriate to comply with the requirements of any other
jurisdiction in which the Company may be required to qualify."

         2. Second Amended and Restated Limited Liability Company Agreement. In
all other respects, the Second Amended and Restated Limited Liability Company
Agreement remains in full force and effect.

         3. Counterparts. This Agreement may be executed in two or more separate
counterparts, each of which shall constitute an original and all of which, when
taken together, shall constitute one Agreement.

         4. Governing Law. THIS AGREEMENT SHALL BE CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF DELAWARE, WITHOUT REGARD TO CONFLICT OF LAW PROVISIONS
THEREOF.

                       [Signatures on the following page.]






         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above written.



                                            AT&T CORP.


                                            By:/s/ ROBERT FEIT
                                               ------------------------------
                                               Name:  Robert Feit
                                               Title: General Attorney and
                                                      Assistant Secretary


                                            ITELTECH, LLC


                                            By:/s/ ROBERT FEIT
                                               ------------------------------
                                               Name:  Robert Feit
                                               Title: President


                                            IDT DOMESTIC-UNION, LLC


                                            By:  IDT Domestic Telecom, Inc., its
                                                    Managing Member

                                            By:/s/ MOTTI LICHTENSTEIN
                                               ------------------------------
                                               Name:  Motti Lichtenstein
                                               Title: CEO


                                            IDT CORPORATION


                                            By:/s/ JAMES A. COURTER
                                               ------------------------------
                                               Name:  James A. Courter
                                               Title: Chief Executive Officer
                                                      and Vice Chairman





                                            IDT INVESTMENTS INC.


                                            By:/s/ ANTHONY S. DAVIDSON
                                               ------------------------------
                                               Name:  Anthony S. Davidson
                                               Title: Vice President and CFO


                                            LMC ANIMAL PLANET, INC.


                                            By:/s/ ELIZABETH M. MARKOWSKI
                                               ------------------------------
                                               Name:  Elizabeth M. Markowski
                                               Title: Senior Vice President


                                            LIBERTY MEDIA CORPORATION


                                            By:/s/ ELIZABETH M. MARKOWSKI
                                               ------------------------------
                                               Name:  Elizabeth M. Markowski
                                               Title: Senior Vice President