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Network Working Group                                            S. CobbRequest for Comments: 1877                                     MicrosoftCategory: Informational                                    December 1995PPP Internet Protocol Control Protocol Extensions forName Server AddressesStatus 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 Contents1.     Additional IPCP Configuration options .................11.1         Primary DNS Server Address ....................21.2         Primary NBNS Server Address ...................31.3         Secondary DNS Server Address ..................41.4         Secondary NBNS Server Address .................5     REFRENCES ....................................................6     SECURITY CONSIDERATIONS ......................................6     CHAIR'S ADDRESS ..............................................6     AUTHOR'S ADDRESS .............................................61.  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.Cobb                         Informational                      [Page 1]

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      6Cobb                         Informational                      [Page 2]

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 peerCobb                         Informational                      [Page 3]

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.Cobb                         Informational                      [Page 4]

RFC 1877                  PPP IPCP Extensions              December 19951.4.  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.Cobb                         Informational                      [Page 5]

RFC 1877                  PPP IPCP Extensions              December 1995References   [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.comAuthor'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.comCobb                         Informational                      [Page 6]