kern/115413: [ipv6] ipv6 pmtu not working

JINMEI Tatuya / 神明達哉 jinmei at
Wed Aug 22 23:34:37 PDT 2007

At Tue, 21 Aug 2007 18:35:05 +0200,
Daniel Hartmeier <daniel at> wrote:

> > But I'm not sure if I understood well - you suspect that only 8 bytes of
> > tcp header are copied from the original tcp packet to the icmp message
> > by the router?
> No, the router is only required (by the RFCs) to quote the first 8 bytes
> of the TCP header.

This is not true for IPv6.  From Section 2.4 of RFC4443:

   (c) Every ICMPv6 error message (type < 128) MUST include as much of
       the IPv6 offending (invoking) packet (the packet that caused the
       error) as possible without making the error message packet exceed
       the minimum IPv6 MTU [IPv6].

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					jinmei at

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