North American Network Operators Group
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Re: an effect of ignoring BCP38

  • From: Pekka Savola
  • Date: Thu Sep 11 09:33:14 2008
On Thu, 11 Sep 2008, Jo Rhett wrote:
[Pekka:]
Loose mode URPF is [..] (IMHO) pretty much waste of time and is confusing the discussion about real spoofing protection. The added protection compared to ACLs that drop private and possibly bogons is not that big and it causes transient losses when the routing tables are changing.

I disagree. But I will say that if everyone would apply strict mode or ACLs to their end point interfaces, this would likely make most of the loose mode irrelevant.

FWIW, based on off-list discussion, Jo's disagreement seems to stem from a misunderstanding of how loose uRPF works (he didn't know it accepts any packet that has a route in the routing table).

--
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings