Re: [tcpm] tcp-auth-opt issue: support for NATs
Eric Rescorla <ekr@networkresonance.com> Thu, 07 August 2008 19:08 UTC
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Date: Thu, 07 Aug 2008 12:09:41 -0700
From: Eric Rescorla <ekr@networkresonance.com>
To: Joe Touch <touch@ISI.EDU>
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Cc: Adam Langley <agl@imperialviolet.org>, tcpm@ietf.org
Subject: Re: [tcpm] tcp-auth-opt issue: support for NATs
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At Thu, 07 Aug 2008 11:51:34 -0700, Joe Touch wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > > Eric Rescorla wrote: > ... > |> Supporting NATs can be done in two different ways: > | > | I think this is at least potentially an issue even aside from NAT. When > | I install keys on my host, you're proposing that I need to configure > | both the peer IP address and the key-id. This isn't necessarily > | bad, but it does mean that if (for instance) the other side decides > | to renumber, nothing will work absent manual reconfiguration. Is > | that something people want? > > <indiv hat on> > If we ignore source IP addresses, we probably end up needing to go > through a set of possible keys when a SYN arrives. Well, not if you use unique key-ids. > This seems like it > amplifies the impact of a SYN attack - the more keys we have, the more > each falsly-encrypted SYN costs. Well, that's certainly true at some level, but if you use any randomness at all in key-id assignment, you would expect to have about N/256 key-ids where N is the number of keys. Unless N is very large, the number of duplicate key-ids is likely to be high enough that this doesn't seem like a very impressive attack, especially since the attacker can force you to compute a MAC with *every* packet he sends, not just SYNs. > Alternately, a good KMS could figure out when these IP addresses > changed, and update the TSAD accordingly. I would prefer this latter > solution... Yeah, but what does that say about manual key management, which is what we're going to have for the foreseeable future. -Ekr _______________________________________________ tcpm mailing list tcpm@ietf.org https://www.ietf.org/mailman/listinfo/tcpm
- [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch
- Re: [tcpm] tcp-auth-opt issue: support for NATs Adam Langley
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Anantha Ramaiah (ananth)
- Re: [tcpm] tcp-auth-opt issue: support for NATs Dan Wing
- Re: [tcpm] tcp-auth-opt issue: support for NATs Dan Wing
- Re: [tcpm] tcp-auth-opt issue: support for NATs Ron Bonica
- Re: [tcpm] tcp-auth-opt issue: support for NATs Eric Rescorla
- Re: [tcpm] tcp-auth-opt issue: support for NATs Dan Wing
- Re: [tcpm] tcp-auth-opt issue: support for NATs Ted Faber
- Re: [tcpm] tcp-auth-opt issue: support for NATs Dan Wing
- Re: [tcpm] tcp-auth-opt issue: support for NATs Joe Touch