Source based routing

[amcsystemstech]

Hello,

I have a remote site with a Cisco 1720 connected to a Frame Relay network. This remote site has a local cable modem with dynamic IP for Internet access. A route in the Cisco 1720 forwards all Internet traffic to the cable Internet service, which is located on the Ethernet side of the 1720.

The central or main site on the Frame Relay has a T1 Internet connection with a static IP. This T1 Internet is shared on the Frame Relay network to all remote sites.

I have a server located at the remote site that needs a static IP to communicate with another server on the Internet. I cannot use the cable modem's Internet access to connect because it does not have a static IP. I want to use source based routing to forward Internet traffic for the server only** to the T1 connection at the central or main site on the Frame.

Here is what I've come up with to enable this on the Cisco 1720:

1. Create an access-list for the server's IP. There are currently no access-list's defined in the router.

access-list 1 permit ip <IP of server>

2. Create a route-map for the server.

route-map ConsumerReach permit 10

3. Match statement for the server IP.

match ip address 1

4. set statement for the action to be performed on matching packets.

set ip next-hop <Serial IP for Inernet Router>

5. Enter interface config mode for the Ethernet Interface.

interface FastEthernet0

6. Apply a policy for the route-map.

ip policy route-map ConsumerReach

Does this look correct or do I need to seek more help before attempting this? On the "set ip next-hop" statement, should I use the "default" keyword? I apologize if none of this makes any sense, I'm new at this.

Thank you,

Andrew M. Campbell

[tbaranski · Accepted solution]

Looks good. Just make sure the route-map is applied to the inbound interface; i.e., the interface on which server-originated traffic enters the router.

You don't want the "default" keyword here -- just 'set ip next-hop ' will suffice.

[michael.whittle]

Hi Andrew,

That looks perfect except don't use the "default" keyword. That's used if you don't have an explicit route to the destination. You can either use the, "set ip next-hop" like you've used or you can use "set interface" command which will also work.

I would also put "ip route-cache policy" on the FastEthernet interface to improve the performance of your policy based routing (PBR). You only need to do this if you're not using CEF which will CEF switch your PBR instead of fast-switch it.

Cheers,

Mike