From: Alex (alex.arseniev@gmail.com)
Date: Wed Nov 29 2006 - 18:14:31 ART
Another possible difference is when a more specific route (say,
192.168.1.128/25) is learned via another router interface (say, E0/2).
My understanding is that both routes will stay in the routing table but the
packet with the source IP of 192.168.1.129 received on E0/0 will be passed
in 1st case but dropped in 2nd case.
Rgds
Alex
----- Original Message -----
From: "Vincent Mashburn" <vmashburn@fedex.com>
To: "mathew Fer" <mathew118@gmail.com>; <ccielab@groupstudy.com>
Sent: Wednesday, November 29, 2006 2:40 PM
Subject: RE: Unicast Reverse Path Forwarding (Unicast RPF) feature
> If these are the only 2 networks connected to E0/0, then the end result
> will be the same, but by no means are they doing the same thing. The
> access-list is only allowing 10.10.20.0/24 and 192.168.1.0/24 to be
> allowed into E0/0. The uRPF looks at the source IP address from each
> packet and verifies that it came in on the interface that matches the
> associated routing table destination.
>
> Vince Mashburn
> Sr. Voice / Data Engineer
> 901-263-5072
> CCVP, CCNP
> Cisco IP Telephony Support Specialist
> Cisco IP Telephony Operations Specialist
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> mathew Fer
> Sent: Wednesday, November 29, 2006 1:03 AM
> To: ccielab@groupstudy.com
> Subject: Unicast Reverse Path Forwarding (Unicast RPF) feature
>
> Hi GS,
>
> Is these 2 same?
>
> As I understand they are the same and this single command makes things
> easy
> for us.
>
> 1.
>
> !
> interface Ethernet 0/0
> ip address 10.10.20.1 255.255.255.0
> ip address 192.168.1.254 255.255.255.0 secondary
> ip access-group FILTER in
> !
> ip access-list standard FILTER
> permit 10.10.20.0 0.0.0.255 any
> permit 192.168.1.0 0.0.0.255 any
> !
>
> 2.
>
> !
> interface Ethernet 0/0
> ip address 10.10.20.1 255.255.255.0
> ip address 192.168.1.254 255.255.255.0 secondary
> ip verify unicast reverse-path
> !
>
> Thank you for the reply.
>
> mathew
>
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