Problem Isolation in RIP Environments

There are a number of commands available in the Cisco IOS with which to isolate and troubleshoot problems in RIP networks. Table 6.2 lists the various show command options for RIP.

Table 6.2 : Show Commands and Explanations

Command	Explanation
show ip rip	Displays all RIP routes. This command also displays this information for routes redistributed into RIP.
show ip protocols	Displays current RIP status. It includes RIP timer, filtering, version, RIP enabled interface, and RIP peer information.
show ip interface	Displays the details of all the interfaces of the router.

We will now discuss sample output of the various show commands.

Listing 6.1 displays the output of the show ip route rip command.

Listing 6.1 Output for show ip route rip

Router# show ip route rip Router#sh ip route Codes: C - connected, S - static, I - IGRP, R - RIP,  M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF,  IA - OSPF inter area N1 - OSPF NSSA external type 1,  N2 - OSPF NSSA external type 2 E1 - OSPF external type 1,  E2 - OSPF external type 2,  E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2,  ia - IS-IS inter area * - candidate default, U - per-user static route,  o - ODR P - periodic downloaded static route Gateway of last resort is not set.   R  150.150.1.0/24 [120/1] via 150.150.2.1, 03:20:04, Serial1   R  150.150.4.0/24 [120/1] via 150.150.3.3, 03:20:04, Serial0

Listing 6.2 displays the output of the show ip protocols command.

Listing 6.2 Output for show ip protocols

 router> show ip protocols Routing Protocol is "rip" Sending updates every 30 seconds with +/-50%,  next due in 35 seconds Timeout after 180 seconds, garbage collect after 120 seconds Outgoing update filter list for all interface is not set Incoming update filter list for all interface is not set Default redistribution metric is 1 Redistributing: kernel connected Default version control: send version 2, receive version 2 Interface        Send  Recv Routing for Networks: eth0 eth1 1.1.1.1 203.181.89.241 Routing Information Sources: Gateway BadPackets BadRoutes  Distance Last Update

Listing 6.3 displays the output of the show ip interface command.

Listing 6.3 Output for show ip interface

Router# show ip interface Ethernet0 is up, line protocol is up  Internet address is 10.0.1.10, subnet mask is 255.255.255.0  Broadcast address is 255.255.255.255  Address determined by setup command  MTU is 1500 bytes  Helper address is not set  Directed broadcast forwarding is enabled  Multicast groups joined: 224.0.0.1 224.0.0.2  Outgoing access list is not set  Inbound access list is not set  Proxy ARP is enabled  Security level is default  Split horizon is enabled  ICMP redirects are always sent  ICMP unreachables are always sent  ICMP mask replies are never sent  IP fast switching is enabled  IP fast switching on the same interface is disabled  IP SSE switching is disabled  Router Discovery is disabled  IP accounting is disabled  TCP/IP header compression is disabled  Probe proxy name replies are disabled  Gateway Discovery is disabled  Serial0 is up, line protocol is up  Internet address is 200.2.2.1, subnet mask is 255.255.255.0  Broadcast address is 255.255.255.255  Address determined by setup command  MTU is 1500 bytes  Helper address is not set  Directed broadcast forwarding is enabled  Multicast groups joined: 224.0.0.1 224.0.0.2  Outgoing access list is not set  Inbound  access list is not set  Proxy ARP is enabled  Security level is default  Split horizon is enabled  ICMP redirects are always sent  ICMP unreachables are always sent  ICMP mask replies are never sent  IP fast switching is enabled  IP fast switching on the same interface is disabled  IP SSE switching is disabled  Router Discovery is disabled  IP accounting is disabled  TCP/IP header compression is disabled  Probe proxy name replies are disabled  Gateway Discovery is disabled

At times, monitoring is not enough to trace a problem. In such circumstances you need to debug the different events of RIP. Table 6.3 lists the different debug commands that can be used for thorough packet level troubleshooting for problems in RIP networks.

Table 6.3 : Debug Commands and Explanations

Command	Explanation
debug rip events {}	This command displays RIP routing transactions. Sending and receiving packets, timers, and changes in interfaces are events shown.
debug rip packet {}	This command displays detailed information about the RIP packets. The origin and port number of the packet as well as a packet dump are displayed.
debug rip zebra {}	This command displays communication between rip and zebra. The main information will include addition and deletion of paths to the kernel and the sending and receiving of interface information.
show debugging rip {}	This command displays all information currently set for debug in RIP.