Subject: NAT64 and ICMP

From: marcelo bagnulo <[email-masked]>
Date: Fri, 28 Mar 2008 19:12:35 +0100

Hi,
another issue that was brought up by thomas in the v6ops meeting is 
w.r.t. ICMP translation.

With this respect, RFC4966 states:

   o  As described in Section 2.2 of [NATP-APP], there are no
      equivalents in IPv6 for some ICMP(v4) messages, while for others
      (notably the 'Parameter Problem' messages) the semantics are not
      equivalent.  Translation of such messages may lead to the loss of
      information.  However, this issue may not be very severe because
      the error messages relate to packets that have been translated by
      NAT-PT rather than by arbitrary packets.  If the NAT-PT is
      functioning correctly, there is, for example, no reason why IPv6
      packets with unusual extension headers or options should be
      generated.

So, do you think we need to impose more stringent requirement on ICMP 
translation than what NATPT/SIIT does? would it be possible to do any 
better?

suggestions are welcome

thanks, marcelo

---

From: Brian E Carpenter <[email-masked]>
Date: Mon, 31 Mar 2008 11:17:23 +1300

> translation than what NATPT/SIIT does? would it be possible to do any

I don't think so. The only thing I noted when writing the SHANTI draft
was that the translator will have to perform port demultiplexing
in order to dispatch ICMP messages translated from IPv4 to the
correct  IPv6 host. But that is a standard NAPT issue.

   Brian