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ICMP Traceback

Document Charter ICMP Traceback WG (itrace)
Title ICMP Traceback
Last updated 2003-09-30
State Approved
WG State Concluded
IESG Responsible AD (None)
Charter edit AD (None)
Send notices to (None)


It is often useful to learn the path that packets take through the
Internet. This is especially important for dealing with certain
denial-of-service attacks, where the source IP is forged. There are
other uses as well, including path characterization and detection of
asymmetric routes. There are existing tools, such as traceroute, but
these generally provide the forward path, not the reverse.

We propose an ICMP Traceback message to help solve this problem.
When forwarding packets, routers can, with a low probability,
generate a Traceback message that is sent along to the destination.
With enough Traceback messages from enough routers along the path,
the traffic source and path can be determined.

The output of this group will be a standards-track RFC describing
the format of such a message, along with guidelines for generation
and interpretation of such messages.

Major issues to be addressed include end user privacy, the desire of
some ISPs to keep their network structure proprietary, authentication
of these messages, and the structure of any necessary PKI.