Re: ICMP_UNREACH_NEEDFRAG returns iface MTU instead of route?

[Dave Huang <khym%azeotrope.org@localhost>]

On Sun, Dec 22, 2013 at 01:05:18PM -0500, Dennis Ferguson wrote:
> What I do know is that it is inappropriate for a router to enforce
> PMTUs discovered by its local applications on packets originated by other
> hosts, and that the route MTU on some routes seems to be coming from
> PMTU Discovery.  I admit the argument that being bug-for-bug compatible
> with Linux and/or FreeBSD is useful might have some merit, however.

That I agree with... Is there a way to view the PMTU route cache? In
Linux, it's "ip route show cache", and Windows has "netsh interface
ipv4 show destinationcache", but I didn't spot anything relevant in
"apropos mtu" on NetBSD. If I knew what was in the PMTU cache, I could
do a test to see whether the cached MTU affected forwarded packets.

In any case, I think there's agreement that there's a bug, if not
exactly what the bug is. I'll file a PR about it :)
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