RFC 1877 (rfc1877) - Page 2 of 6

PPP Internet Protocol Control Protocol Extensions for Name Server Addresses

RFC 1877                  PPP IPCP Extensions              December 1995


   Primary and secondary addresses are negotiated independently.  They
   serve identical purposes, except that when both are present an
   attempt SHOULD be made to resolve names using the primary address
   before using the secondary address.

   For implementational convenience, these options are designed to be
   identical in format and behavior to option 3 (IP-Address) which is
   already present in most IPCP implementations.

   Since the usefulness of name server address information is dependent
   on the topology of the remote network and local peer's application,
   it is suggested that these options not be included in the list of
   "IPCP Recommended Options".

1.1.  Primary DNS Server Address

   Description

      This Configuration Option defines a method for negotiating with
      the remote peer the address of the primary DNS server to be used
      on the local end of the link.  If local peer requests an invalid
      server address (which it will typically do intentionally) the
      remote peer specifies the address by NAKing this option, and
      returning the IP address of a valid DNS server.

      By default, no primary DNS address is provided.

   A summary of the Primary DNS Address Configuration Option format is
   shown below.  The fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |      Primary-DNS-Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Primary-DNS-Address (cont)   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      129

   Length

      6






Cobb                         Informational