RFC 2428 (rfc2428) - Page 2 of 8

FTP Extensions for IPv6 and NATs

RFC 2428            FTP Extensions for IPv6 and NATs      September 1998


   This document provides a specification for a way that FTP can
   communicate data connection endpoint information for network
   protocols other than IPv4.  In this specification, the FTP commands
   PORT and PASV are replaced with EPRT and EPSV, respectively.  This
   document is organized as follows.  Section 2 outlines the EPRT
   command and Section 3 outlines the EPSV command.  Section 4 defines
   the utilization of these two new FTP commands.  Section 5 briefly
   presents security considerations.  Finally, Section 6 provides
   conclusions.

2.  The EPRT Command

   The EPRT command allows for the specification of an extended address
   for the data connection.  The extended address MUST consist of the
   network protocol as well as the network and transport addresses.  The
   format of EPRT is:

           EPRT

   The EPRT command keyword MUST be followed by a single space (ASCII
   32).  Following the space, a delimiter character () MUST be
   specified.  The delimiter character MUST be one of the ASCII
   characters in range 33-126 inclusive.  The character "|" (ASCII 124)
   is recommended unless it coincides with a character needed to encode
   the network address.

   The  argument MUST be an address family number defined by
   IANA in the latest Assigned Numbers RFC (RFC 1700 [RP94] as of the
   writing of this document).  This number indicates the protocol to be
   used (and, implicitly, the address length).  This document will use
   two of address family numbers from [RP94] as examples, according to
   the following table:

        AF Number   Protocol
        ---------   --------
        1           Internet Protocol, Version 4 [Pos81a]
        2           Internet Protocol, Version 6 [DH96]

   The  is a protocol specific string representation of the
   network address.  For the two address families specified above (AF
   Number 1 and 2), addresses MUST be in the following format:

        AF Number   Address Format      Example
        ---------   --------------      -------
        1           dotted decimal      132.235.1.2
        2           IPv6 string         1080::8:800:200C:417A
                    representations
                    defined in [HD96]



Allman, et. al.             Standards Track