nanog mailing list archives

RE: Cisco - ip verify unicast reverse-path


From: Paul Ferguson <ferguson () cisco com>
Date: Mon, 14 Feb 2000 14:00:29 -0500


At 09:58 AM 02/14/2000 -0800, Owen DeLong wrote:

                Does ip verify unicast reverse path accept packets for which
        the inbound interface is not the preferred outbound interface, but
        is a valid outbound interface?

This feature looks up the source address in FIB, and if the
source address is reachable via the source interface, the
packet is forwarded. If it is not, it is punted.

Yes, it can occasionally pose problems in situations where the
FIB associates the forwarding path for a particular prefix to
an interface which is not the one on which the packet was received.

This feature is not a panacea, just another tool.

- paul




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