Network Working Group                                            S. Cobb
Request for Comments: 1877                                     Microsoft
Category: Informational                                  December 1995


         PPP Internet Protocol Control Protocol Extensions for
                         Name Server Addresses

 Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

 Abstract

   The Point-to-Point Protocol (PPP) [1] provides a standard method for
   transporting multi-protocol datagrams over point-to-point links.  PPP
   defines an extensible Link Control Protocol and a family of Network
   Control Protocols (NCPs) for establishing and configuring different
   network-layer protocols.

   This document extends the NCP for establishing and configuring the
   Internet Protocol over PPP [2], defining the negotiation of primary
   and secondary Domain Name System (DNS) [3] and NetBIOS Name Server
   (NBNS) [4] addresses.

 Table of Contents

     1.     Additional IPCP Configuration options .................    1
        1.1         Primary DNS Server Address ....................    2
        1.2         Primary NBNS Server Address ...................    3
        1.3         Secondary DNS Server Address ..................    4
        1.4         Secondary NBNS Server Address .................    5
     REFRENCES ....................................................    6
     SECURITY CONSIDERATIONS ......................................    6
     CHAIR'S ADDRESS ..............................................    6
     AUTHOR'S ADDRESS .............................................    6

1.  Additional IPCP Configuration Options

   The four name server address configuration options, 129 to 132,
   provide a method of obtaining the addresses of Domain Name System
   (DNS) servers and (NetBIOS Name Server (NBNS) nodes on the remote
   network.






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   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






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RFC 1877                  PPP IPCP Extensions              December 1995


   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.

1.2.  Primary NBNS Server Address

   Description

      This Configuration Option defines a method for negotiating with
      the remote peer the address of the primary NBNS 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 NBNS server.

      By default, no primary NBNS address is provided.

   A summary of the Primary NBNS 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-NBNS-Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Primary-NBNS-Address (cont)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      130

   Length

      6

   Primary-NBNS-Address

      The four octet Primary-NBNS-Address is the address of the primary
      NBNS server to be used by the local peer.  If all four octets are
      set to zero, it indicates an explicit request that the peer



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RFC 1877                  PPP IPCP Extensions              December 1995


      provide the address information in a Config-Nak packet.

   Default

      No address is provided.

1.3.  Secondary DNS Server Address

   Description

      This Configuration Option defines a method for negotiating with
      the remote peer the address of the secondary 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 secondary DNS address is provided.

   A summary of the Secondary 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     |      Secondary-DNS-Address
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Secondary-DNS-Address (cont) |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      131

   Length

      6

   Secondary-DNS-Address

      The four octet Secondary-DNS-Address is the address of the primary
      NBNS 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.



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1.4.  Secondary NBNS Server Address

   Description

      This Configuration Option defines a method for negotiating with
      the remote peer the address of the secondary NBNS 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 NBNS server.

      By default, no secondary NBNS address is provided.

   A summary of the Secondary NBNS 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     |      Secondary-NBNS-Address
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        Secondary-NBNS-Address (cont) |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Type

         132

      Length

         6

      Secondary-NBNS-Address

         The four octet Secondary-NBNS-Address is the address of the
         secondary NBNS 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.








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References

   [1] Simpson, W., Editor, "The Point-to-Point Protocol (PPP)", STD 51,
       RFC 1661, Daydreamer, July 1994.

   [2] McGregor, G., "PPP Internet Control Protocol", RFC 1332, Merit,
       May 1992.

   [3] Auerbach, K., and A. Aggarwal, "Protocol Standard for a NetBIOS
       Service on a TCP/UDP Transport", STD 19, RFCs 1001 and 1002,
       March 1987.

   [4] Mockapetris, P., "Domain Names - Concepts and Facilities", STD
       13, RFC 1034, USC/Information Sciences Institute, November 1987.

   [5] Mockapetris, P., "Domain Names - Implementation and
       Specification", STD 13, RFC 1035, USC/Information Sciences
       Institute, November 1987.

Security Considerations

   Security issues are not discussed in this memo.

Chair's Address

   The working group can be contacted via the current chair:

      Fred Baker
      Cisco Systems
      519 Lado Drive
      Santa Barbara, California  93111

      EMail: fred@cisco.com

Author's Address

   Questions about this memo can also be directed to:

      Steve Cobb
      Microsoft Corporation
      One Microsoft Way
      Redmond, WA  98052-6399

      Phone: (206) 882-8080

      EMail: stevec@microsoft.com





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PPP Internet Protocol Control Protocol Extensions for Name Server Addresses

RFC TOTAL SIZE: 10591 bytes
PUBLICATION DATE: Monday, December 18th, 1995
LEGAL RIGHTS: The IETF Trust (see BCP 78)