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Re: A problem with public key encrption in IKE



     
Pau-Chen,

      <<
        I think you may have a point here. But if I understand your scenario 
        correctly, the gateway has to initiate the IKE exchange with the 
        remote host of which
        the gateway knows nothing. So the gateway may have difficulty in 
        determining what to propose. Of course, a catch-all wildcard entry 
        in the gateway's policy may solve the problem; but I am not too sure 
        about the wildcard's security implication.
      >>
     
Well, let's think about this...

It seems that IPSEC implementations select the protection requirements 
(what they will propose/accept) for phase 1 and phase 2 together, based on 
the identity of the peer.  I don't know if this is required by one of the 
RFCs, or if that's just the way it's done.

It would make sense, though, to determine the protection requirements for 
each phase separately.  The protection requirements for phase 1 could be 
determined independently of the identity of the peer.  (After all, one 
purpose of phase 1 is to determine the identity of the peer.)  The phase 1 
requirements would not be specified by the SPD, they would be selected by 
the IPSEC administrator by means that need not be part of the IPSEC 
standard.  Then the protection requirements for phase 2 could be determined 
based on the identity of the peer established in phase 1. These requirments 
would be specified by the SPD.

Is this allowed by the RFCs?

Francisco



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