Once upon a time, John Kristoff <jtk@aharp.is-net.depaul.edu> said:
It might be nice if all router vendors were able to associate the interface configured address(es)/nets as a variable for ingress filters. So for in the Cisco world, a simple example would be:
interface Serial0 ip address 192.0.2.1 255.255.255.128 ip access-group 100 in ! interface Serial1 ip address 192.0.2.129 255.255.255.128 ip access-group 100 in ! access-list 100 permit ip $interface-routes any access-list 100 deny ip any any
How is this different than "ip verify unicast reverse-path" (modulo CEF problems and bugs, which of course NEVER happen :-) )? Multihomed customers are more interesting, but if all the single homed customers had uRPF (or $VENDOR's equivalent) enabled it would cut down on a significant amount of the spoofed traffic. -- Chris Adams <cmadams@hiwaay.net> Systems and Network Administrator - HiWAAY Internet Services I don't speak for anybody but myself - that's enough trouble.