Thursday, July 10, 2008

Unicast Reverse Path Forwarding-Tutorial - CCIE Candidate

CCIE Candidate - Unicast Reverse Path Forwarding-Tutorial
Unicast Reverse Path Forwarding is a small security feature
When configured on an interface, the router checks the incoming packet’s source address with its routing table. If the incoming packet’s source is reachable via the same interface it was received, the packet is allowed. URPF provides protection again spoofed packets with unverifiable source.
Though basically a single line command, URPF can be a little confusing when used with access-list feature if order of operation is not understood completely.

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