draft-ietf-v6ops-ivi-icmp-address-05.txt   draft-ietf-v6ops-ivi-icmp-address-06.txt 
Network Working Group X. Li Network Working Group X. Li
Internet-Draft C. Bao Internet-Draft C. Bao
Intended status: BCP CERNET Center/Tsinghua Intended status: BCP CERNET Center/Tsinghua
Expires: March 10, 2013 University Expires: March 15, 2013 University
D. Wing D. Wing
R. Vaithianathan R. Vaithianathan
Cisco Cisco
G. Huston G. Huston
APNIC APNIC
September 6, 2012 September 11, 2012
Stateless Source Address Mapping for ICMPv6 Packets Stateless Source Address Mapping for ICMPv6 Packets
draft-ietf-v6ops-ivi-icmp-address-05 draft-ietf-v6ops-ivi-icmp-address-06
Abstract Abstract
A stateless IPv4/IPv6 translator may receive ICMPv6 packets A stateless IPv4/IPv6 translator may receive ICMPv6 packets
containing non IPv4-translatable addresses as the source. These containing non IPv4-translatable addresses as the source. These
packets should be passed across the translator as ICMP packets packets should be passed across the translator as ICMP packets
directed to the IPv4 destination. This document presents directed to the IPv4 destination. This document presents
recommendations for source address translation in ICMPv6 headers to recommendations for source address translation in ICMPv6 headers to
handle such cases. handle such cases.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 10, 2013. This Internet-Draft will expire on March 15, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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the origin rather than simply blackholing at or beyond the the origin rather than simply blackholing at or beyond the
translator. In the future, a new ICMP extension whose presence translator. In the future, a new ICMP extension whose presence
indicates that the packet has been translated and that the source indicates that the packet has been translated and that the source
address belongs to the translator, not the originating node can also address belongs to the translator, not the originating node can also
be considered. be considered.
5. Stateless Address Mapping Algorithm 5. Stateless Address Mapping Algorithm
If a pool of public IPv4 addresses is configured on the translator, If a pool of public IPv4 addresses is configured on the translator,
it is RECOMMENDED to randomly select the IPv4 source address from the it is RECOMMENDED to randomly select the IPv4 source address from the
pool. This can somehow avoid the appearance of a routing loop in pool. Random selection reduces the probability that two ICMP
tools unaware of the ICMP extension such as traceroute, even though messages elicited by the same TRACEROUTE might specify the same
those addresses do not really show the actual topology apart from the source address and, therefore, erroneously present the appearance of
hop count. An enhanced traceroute application is RECOMMENDED in a routing loop. An enhanced traceroute application is RECOMMENDED in
order to obtain the IPv6 source addresses which generated the ICMPv6 order to obtain the IPv6 source addresses which generated the ICMPv6
messages. messages.
6. Security Considerations 6. Security Considerations
This document recommends the generation of IPv4 ICMP messages from This document recommends the generation of IPv4 ICMP messages from
IPv6 ICMP messages. These messages would otherwise have been IPv6 ICMP messages. These messages would otherwise have been
discarded. It is not expected that new considerations result from discarded. It is not expected that new considerations result from
this change. As with a number of ICMP messages, a spoofed source this change. As with a number of ICMP messages, a spoofed source
address may result in replies arriving at hosts that did not expect address may result in replies arriving at hosts that did not expect
 End of changes. 5 change blocks. 
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