EIGRP Route Problem

In certain cases, not all EIGRP routes may be available in the routing table. This may be caused due to nonformation of neighbor relationships.

Look at the example depicted in Figure 8.5. Routers A1 and A2 are part of the EIGRP routing environment represented by a cloud.

Figure 8.5: An EIGRP network depicting route problems.

Observation

In Figure 8.5, the route for network 10.10.1.0/24 is not available in the routing table of A1. This is checked using the show ip route 10.10.1.0/24 command.

Problem Isolation

The steps to isolate the route problem are:

1. Check if any EIGRP routes are available in A1 by using the A1#show ip route eigrp command.

2. Check the EIGRP topology table by using the A1#show ip eigrp topology command, if there are no routes available at A1.

3. Check and verify the neighbor relationships of A1 if an empty topology table is viewed. The neighbor relationships can be checked as discussed in the previous section.

4. Check and fix the distribute lists in both inbound and outbound directions if neighbor relationships are OK. The distribute lists are checked by using the show ip protocols command. The output of the show ip protocols command is shown in Listing 8.27.

   Listing 8.27 Output of show ip protocols Command at A1

   A1#show ip protocols  Routing Protocol is "eigrp 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set 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: static, eigrp 300 Automatic network summarization is in effect Maximum path: 4 Routing for Networks: 10.10.1.0 Passive Interface(s): Ethernet0 Routing Information Sources: Gateway         Distance      Last Update 10.10.2.1       90            00:05:35 Distance: internal 90 external 170   

   The output indicates whether any routing update filter is set or not.

5. Check if the local router has the same Router ID (RID) as the originating router. In that case, RID needs to be changed accordingly, and the EIGRP process is restarted.