Using Policy Rules to Provide Routing Solutions
The next-interface, next-hop, filter, and forward rules provide routing solutions for traffic matching a classifier. A classifier can have only one action that provides a routing solution.
If you configure two routing solution rules, such as filter and forward, in the same classifier group, the router displays a warning message, and the rule configured last replaces the previous rule.
For IP policy lists, policy rules are available to enable you to make a forwarding decision that includes the next interface and next hop:
- Forward next interface—Causes an interface to forward all packets that satisfy the classification associated with that rule to the next interface specified
- Forward next hop—Causes an interface to forward all packets that satisfy the classification associated with that rule to the next-hop address specified
For example, you can route packets arriving at IP interface ATM 0/0.0 so that they area handled as indicated:
- Packets from source 1.1.1.1 are forwarded out of interface ATM 0/0.1.
- Packets from source 2.2.2.2 are forwarded out of interface ATM 2/1.1.
- All other packets are dropped.
To configure this routing policy, issue the following commands:
host1(config)#ip classifier-list claclA ip host 1.1.1.1 anyhost1(config)#ip classifier-list claclB ip host 2.2.2.2 anyhost1(config)#ip policy-list IpPolicy100host1(config-policy-list)#classifier-group claclAhost1(config-policy-list-classifier-group)#forward interface atm 0/0.1host1(config-policy-list-classifier-group)#exithost1(config-policy-list)#classifier-group claclBhost1(config-policy-list-classifier-group)#forward interface atm 2/1.1host1(config-policy-list-classifier-group)#exit host1(config-policy-list)#classifier-group *host1(config-policy-list-classifier-group)#filterhost1(config-policy-list-classifier-group)#exithost1(config)#interface atm 0/0.0host1(config-subif)#ip policy input IpPolicy100 statistics enabled