(Loose) uRPF vs. non-announced IXP space

[Daniel Roesen]

On Wed, Feb 08, 2012 at 04:57:46PM +0100, Daniel Roesen wrote:
> On Wed, Feb 08, 2012 at 01:26:11PM +0000, Phil Mayers wrote:
> > On 08/02/12 12:35, Stefan Neufeind wrote:
> >
> >> but why don't those routers source the ICMP-message from a
> >> loopback-address or the like with an "official IP"?
> >
> > Section 2.2 of RFC 4443 suggests (to me) the default for source address of 
> > ICMPv6 messages should be the address of the outgoing interface towards the 
> > destination.

just to clarify...

The address of the outgoing interface towards the ICMP receiver, yes.
Not the address of the triggering packet's destination. If I remember
correctly, an older RFC mandated the latter (and the Linux IPv6 stack
followed that spec before people noticed that this totally breaks
traceroute).

Best regards,
Daniel

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