Re: Adding revised identities to IKEv2

[Michael Thomas <mat@cisco.com>]

Uri Blumenthal writes:
 > At 15:27 11/18/2002 +0100, Francis Dupont wrote:
 > >  In your previous mail you wrote:
 > >
 > >    And replying to Francis - I'm too lazy to check myself, but wasn't cookie
 > >    (which is
 > >    IP address-based) used then as a part of signed contents in IKEv1 
 > > exchange?
 > >
 > >=> the cookie is built by the other peer so the only effect is the
 > >addresses must remain the same between all packets of a phase,
 > >a check which is currently done even between phases.
 > >Can you explain how cookies can forbid an attacker to change en route
 > >or as the peer to put a rogue address in all messages?
 > 
 > 
 > If the cookie is a part of the signed contents, then changing IP address
 > of a packet during IKE exchange will invalidate the signature and will
 > be detected.

Right. Perhaps a distinction should be draw between
subsequent exchanges (eg, main/quick). It's probably
not a hardship to say the IP address must stay stable
during an exchange; what we don't want is to have to
renegotiate a new main mode SA if the IP address
changes.

		Mike