Redistributing Static Routes into RIP

Problem

You want RIP to redistribute static routes that you have configured on your router.

Solution

The redistribute static command tells RIP to forward static routes in addition to the directly connected routes and the routes that have been learned from other RIP routers, which it forwards by default:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#ip route 192.168.10.0 255.255.255.0 172.22.1.4
Router1(config)#router rip
Router1(config-router)#redistribute static
Router1(config-router)#end
Router1#

You can define how these routes look to other routers when they are redistributed:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#ip route 192.168.10.0 255.255.255.0 172.22.1.4
Router1(config)#router rip                  
Router1(config-router)#redistribute static metric 5
Router1(config-router)#distribute-list 7 out static
Router1(config-router)#exit
Router1(config)#access-list 7 permit 192.168.10.0
Router1(config)#end
Router1#

Discussion

The biggest potential problem that you will encounter with redistributing routes into RIP comes from breaking network class boundaries. RIP is classful, so you have to be rather careful about how you distribute routing information from other sources that may be classless. In this recipe, Router1 redistributes a static route for the Class C network 192.168.10.0. But if we tried instead to redistribute a larger range (such as 192.168.12.0/22), RIP would not generate any errors—the router would just quietly refuse to forward this route.

Looking at the RIP database on a router with IOS level 12.0(6)T or higher shows the redistributed static route:

Router1#show ip rip database 192.168.10.0 255.255.255.0
192.168.10.0/24    redistributed
    [5] via 0.0.0.0, 
Router1#

After configuring the second example, the output of show ip protocols includes information about the filtering. This command also tells you what protocols RIP is distributing:

Router1#show ip protocols 
Routing Protocol is "rip"
  Sending updates every 30 seconds, next due in 5 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Outgoing update filter list for all interfaces is not set
    Redistributed static filtered by 7
  Incoming update filter list for all interfaces is not set
  Redistributing: static, rip
  Default version control: send version 2, receive version 2
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0.1     2     2 
    Serial0/0.2           2     2                                    
    FastEthernet0/1       2     2                                    
   Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    172.22.0.0
    172.25.0.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    172.25.1.7           120      00:00:03
    172.25.2.2           120      00:00:06
    172.22.1.4           120      00:00:08
  Distance: (default is 120)
Router1#

In addition to static routes, you can distribute information from other dynamic routing protocols with RIP simply by specifying which protocol's routes you want RIP to use. For example, if you have an EIGRP network that uses process number 65530 on the same router, you would redistribute the EIGRP routes into RIP like this:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#router eigrp 65530
Router1(config-router)#network 192.168.1.0
Router1(config-router)#exit
Router1(config)#router rip
Router1(config-router)#redistribute eigrp 65530
Router1(config-router)#end
Router1#

If you look at the show ip protocols command, you can see that RIP redistributes routes it learns from EIGRP, but EIGRP does not redistribute routes learned from RIP. If you also want EIGRP to redistribute RIP routes, you must explicitly configure it to do so. 

Router1#show ip protocols   
Routing Protocol is "rip"
  Sending updates every 30 seconds, next due in 0 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Outgoing update filter list for all interfaces is 
  Incoming update filter list for all interfaces is 
  Redistributing: static, rip, eigrp 65530
   

  Default version control: send version 1, receive any version
    Interface        Send  Recv   Key-chain
    FastEthernet0/0.1     2     2 
    Serial0/0.2           2     2                                    
    FastEthernet0/1       2     2                                    
   Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    172.22.0.0
    172.25.0.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    172.25.1.7           120      00:00:03
    172.25.2.2           120      00:00:06
    172.22.1.4           120      00:00:08
  Distance: (default is 120)
   
Routing Protocol is "eigrp 65530"
  Outgoing update filter list for all interfaces is 
  Incoming update filter list for all interfaces is 
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
  EIGRP maximum hopcount 100
  EIGRP maximum metric variance 1
  Redistributing: eigrp 65530
  Automatic network summarization is in effect
  Routing for Networks:
    192.168.1.0
  Routing Information Sources:
    Gateway         Distance      Last Update
  Distance: internal 90 external 170