Incoming routing

[ab.techstuff]

I'm sure this has been asked before but I couldn't figure out the keywords needed for the search. 

Currently I have a default route set like

ip route 0.0.0.0 0.0.0.0 12.161.x.x #<g0/0/0> 

this works fine, but I want to say that if the router receives any packets from 172.x.x.x / 20 send instead to 10.1.1.1 <g0/1/0>

I think this is an ACL waiting to happen but I'm not sure exactly how to configure it.

I don't have any advanced features on the router, so I can't enable vrf or anything like that. It's a 2901. 

Thanks in advance for any help. 

[Dennis Mink]

What you are looking for is called, policy based routing,

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/10116-36.html

and you are correct part of its configuration is done, using ACLs

[paul driver · Accepted solution]

Hello

As stated sounds like PBR would be applicable.

Example:

ip sla 1
icmp-echo 10.1.1.1 <-- tracked destination
ip sla schedule 1 life forever start-time now

track 5 sla 1 reachability

access-list 10 permit 172.x.x.x 0.0.15.255

route-map PBR permit 10
match ip address 10
set ip next-hop verify-availability 10.1.1.1 1 track 5

int x/x
Description 172.x.x.x incoming interface
ip polcy route-map PBR
exit

[ab.techstuff]

Thanks guys, I will try this and report back. 

[ab.techstuff]

What if the route is coming in through a BGP connection so there is no interface on the router that matches the subnet that I want to apply a policy route to. Does that work? This is impossible to test in packet tracer and hard to get close to my configuration in GNS3.