Troubleshooting Routing Information Protocol (RIP)

Commands that you can use to gather information about the Routing Information Protocol (RIP) routing protocol in order to assist in your troubleshooting and problem resolution are covered.

Getting network information

To start this process, look at the ip route command, which in addition to listing routes, can display summary information letting you know how many RIP-based networks exist in the routing table.

Router2>enable
Password:
Router2#show ip route summary
IP routing table name is Default-IP-Routing-Table(0)
IP routing table maximum-paths is 16
Route Source    Networks    Subnets     Overhead    Memory (bytes)
connected       2           0           144         272
static          1           0           72          136
rip             1           0           72          136
Total           4           0           288         544

To ensure that the routing protocol is up and functioning, use the show ip protocols command, which provides similar output to the following. However, first note some important things to look for in the output:

Timers and when the next update will be sent to neighboring routers
Version of RIP in use
Interfaces in use for RIP
Networks being routed by RIP
Address from which you are receiving RIP information

Router2>enable
Password:

Router2#show ip protocols
Routing Protocol is "rip"
  Sending updates every 30 seconds, next due in 12 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Redistributing: rip
  Default version control: send version 2, receive version 2
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       2     2
    FastEthernet0/1       2     2
  Automatic network summarization is not in effect
  Maximum path: 4
  Routing for Networks:
    192.168.1.0
    192.168.5.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.1.1          120      00:32:42
  Distance: (default is 120)

Note the last item, which lists the administrative distance. This point becomes important when using multiple routing protocols, because each protocol has a different default distance that determines which routing protocol is favored when a remote network is advertised on multiple routing protocols.

Seeing information RIP receives

You can view the contents of the RIP database to find out what information RIP has received. Doing so shows you the networks that are part of RIP, the summarization settings, and from which routers your router has learned routes.

Router2>enable
Password:
Router2#show ip rip database
192.168.1.0/24    auto-summary
192.168.1.0/24    directly connected, FastEthernet0/0
192.168.5.0/24    auto-summary
192.168.5.0/24    directly connected, FastEthernet0/1
192.168.10.0/24    auto-summary
192.168.10.0/24
    [1] via 192.168.1.1, 00:00:20, FastEthernet0/0

Debugging RIP

Finally, you have the system debug command. In regard to RIP, the debug command is limited to database changes. In the following output, you see the types of data you can get from debug command, which are also listed here:

The RIP information your router is sending out and the networks included in the update
The RIP version being used
The RIP data being received, including the interface it arrived on, the router it came from, and the networks that are included

If you are using debug through a remote console, you use terminal monitor to see the debug information the remote console's screen.

Router2>enable
Password:
Router2#debug ip rip ?
  database  RIP database events
  events    RIP protocol events
  trigger   RIP trigger extension
  <cr>
Router2#debug ip rip
RIP protocol debugging is on
Router2#
*Mar 17 22:57:39.842: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/1 (192.168.5.1)
*Mar 17 22:57:39.842: RIP: build update entries
*Mar 17 22:57:39.842:   network 192.168.1.0 metric 1
*Mar 17 22:57:39.842:   network 192.168.10.0 metric 2
*Mar 17 22:57:46.870: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.1.240)
*Mar 17 22:57:46.870: RIP: build update entries
*Mar 17 22:57:46.870:   network 192.168.5.0 metric 1
*Mar 17 22:57:53.654: RIP: received v1 update from 192.168.1.1 on FastEthernet0/0
*Mar 17 22:57:53.654:      192.168.10.0 in 1 hops
Router2#no debug ip rip