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auto-defend threshold

Latest reply: Dec 12, 2012 12:11:36 5142 1 0 0 0

I don't know how many of you configured local attack defense on your boxes, but i've discovered an interesting case. If you set auto-defend threshold to a  small value - like 16 pps (default is 128 pps) you will start to receive frequently this kind of logs:

User attack occurred.......(AttackPackets=16 packets per second)

In addition ttl expired counter is increasing every time an attack occured.

So I decided to capture the packets using flow mirroring every time when attack ocurred.

In wireshark can only find OSPF packets - keep alive, lsa update and lsa ack. So i concluded that everytime when ospf lsa-update/ack events occurs logs will spot them as attack. When i modified to 128, no attack event occured.

PIM, OSPF or LDP packets have ttl field = 1 when reach peer device, so will be treated first as ttl-expired packets, but after will be processed by protocol stack after ttl check.


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Created Dec 12, 2012 12:11:36

 Everyone is welcomed to share his cases here on support-e.

Thank you for support!

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