* Valdis Kletnieks:
On Sun, 15 Aug 2010 18:14:41 +0200, Florian Weimer said:
What's the current consensus on exempting private network space from source address validation? Is it recommended? Discouraged?
What you do on your internal networks and internal transit is your business. BCP38 talks about where you connect to the rest of the world.
I'm seeing them across AS boundaries, otherwise I wouldn't have bothered.
RFC 1918 is specific that you're supposed to get all medieval on any escaping packets:
Yeah, but sometimes, the current practice moves on. 8-)
(One argument in favor of exceptions is that it makes PMTUD work if transfer networks use private address space.)
And that connection that's trying to use PMTU got established across the commodity internet, how, exactly? ;)
ICMP "fragmentation needed, but DF set" messages carry the a addresses of intermediate routers which generate them (potentially in response to MTU drops) as source addresses, not the IP addresses of the peers in a connection.
That implies you let some routing info escape and got one of those "ambiguous routing situations".
Not really, I'm afraid.