On Tue, 13 Nov 2007, Drew Weaver wrote:
Is it to be expected to see rfc1918 src'd packets coming from transit carriers?
Yes. Any ISP which uses RFC1918 on "internal" links may generate
various ICMP error packets (e.g. traceroute/TTL expire, PMTU
discovery/Fragmentation required, etc) from router interfaces which have
RFC1918 addresses for transit traffic.
Some people filter them anyway, and get "*"'s in traceroutes and PMTU
weirdness.
#include "old debate about using RFC1918 addresses on transit links"
#include "other old debate about filtering stuff in backbones or edge"
