Network Working Group                                           A. Conta
Request for Comments: 2463                                        Lucent
Obsoletes: 1885                                               S. Deering
Category: Standards Track                                  Cisco Systems
                                                           December 1998


               Internet Control Message Protocol (ICMPv6)
               for the Internet Protocol Version 6 (IPv6)
                             Specification

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

   This document specifies a set of Internet Control Message Protocol
   (ICMP) messages for use with version 6 of the Internet Protocol
   (IPv6).

Table of Contents

      1. Introduction........................................2
      2. ICMPv6 (ICMP for IPv6)..............................2
            2.1 Message General Format.......................2
            2.2 Message Source Address Determination.........3
            2.3 Message Checksum Calculation.................4
            2.4 Message Processing Rules.....................4
      3. ICMPv6 Error Messages...............................6
            3.1 Destination Unreachable Message..............6
            3.2 Packet Too Big Message...................... 8
            3.3 Time Exceeded Message....................... 9
            3.4 Parameter Problem Message...................10
      4. ICMPv6 Informational Messages......................11
            4.1 Echo Request Message........................11
            4.2 Echo Reply Message..........................12
      5. Security Considerations............................13
      6. References.........................................14
      7. Acknowledgments....................................15




 
RFC 2463                 ICMPv6 (ICMP for IPv6)            December 1998


      8. Authors' Addresses.................................16
      Appendix A - Changes since RFC 1885...................17
      Full Copyright Statement..............................18

1. Introduction

   The Internet Protocol, version 6 (IPv6) is a new version of IP.  IPv6
   uses the Internet Control Message Protocol (ICMP) as defined for IPv4
   [RFC-792], with a number of changes.  The resulting protocol is
   called ICMPv6, and has an IPv6 Next Header value of 58.

   This document describes the format of a set of control messages used
   in ICMPv6.  It does not describe the procedures for using these
   messages to achieve functions like Path MTU discovery; such
   procedures are described in other documents (e.g., [PMTU]).  Other
   documents may also introduce additional ICMPv6 message types, such as
   Neighbor Discovery messages [IPv6-DISC], subject to the general rules
   for ICMPv6 messages given in section 2 of this document.

   Terminology defined in the IPv6 specification [IPv6] and the IPv6
   Routing and Addressing specification [IPv6-ADDR] applies to this
   document as well.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC-2119].

2. ICMPv6 (ICMP for IPv6)

   ICMPv6 is used by IPv6 nodes to report errors encountered in
   processing packets, and to perform other internet-layer functions,
   such as diagnostics (ICMPv6 "ping").  ICMPv6 is an integral part of
   IPv6 and MUST be fully implemented by every IPv6 node.

2.1 Message General Format

   ICMPv6 messages are grouped into two classes: error messages and
   informational messages.  Error messages are identified as such by