RFC 1877 (rfc1877) - Page 2 of 6
PPP Internet Protocol Control Protocol Extensions for Name Server Addresses
Alternative Format: Original Text Document
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
