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

Primary-DNS-Address

The four octet Primary-DNS-Address is the address of the primary DNS server to be used by the local peer. If all four octets are set to zero, it indicates an explicit request that the peer provide the address information in a Config-Nak packet.

Default

No address is provided.