An odd IPv6 application issue

Florian Lohoff f at
Sat Dec 11 12:19:15 CET 2010


On Sat, Dec 11, 2010 at 11:18:41AM +0100, Steinar H. Gunderson wrote:
> Den 11. desember 2010 06:06 skrev George Bonser <gbonser at> følgende:
> > It creates an IPv6 socket and communicates with the server via IPv6 but
> > the source address it selects is the converted v4 address.
> This sounds like an operating system bug — mapped addresses are never
> supposed to be seen on the wire. What operating system is this?

I have seen stuff like this happening in MPLS environments (6PE) with
ttl propagation enabled. Intermediate P routers with ipv6 disabled
send back time exceeded with their default v4 loopback mapped.

I found it scaring that routers with explicitly disabled ipv6 were processing
these packets in their ipv6 stack.

But nevertheless we saw mapped v4 on wire.

Florian Lohoff                                                 f at
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