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SA look up



Title: Message
Hi, there,
 
I know I must be wrong somewhere, please kindly correct me:
 
       C 192.168.1.2
       /
      /
     /
    /
   A -----------B  192.168.1.3
192.168.1.1
 
At site A, there exists policy:
From source (192.168.1.1) to destination (ip minmum 192.168.1.2 to - ip maximum 192.168.1.10), any src port, any dst port, any prorocol, use AH-transport mode, and md5-hmac to protect traffic. All the SA selector uses the value associated with the policy entry.
 
Now if A wants to send message to B, SAs will be negotiated between A and B, so there will be an outbound SA at site A. Since the selector value will use the policy entry, the same SA will be used for traffic A -> C.
 
Now the problem comes, when C receives a packet from A, it looks its own inbound SA table by looking <dst IP= C, spi, AH-protocol> ), the SA is NOT there ! The packet will be dropped. And it seems no way to overcome this, because whenever A wants to send message to C, it will locate a SA, which is actually negotiated between A and B.
 
Thanks for your help,
 
Jin Zhang
Elmic Systems USA

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