System information

Troubleshooting TCP/IP 7-129
IP Enhanced IGRP: Routes Missing from Routing Table
IP Enhanced IGRP: Routes Missing from Routing Table
Symptom: Routes are missing from the routing table of routers running Enhanced IGRP. Hosts on
one network cannot access hosts on a different network. Hosts on the same network might or might
not be able to communicate. The problem might occur in internetworks running only Enhanced
IGRP or in an internetwork running Enhanced IGRP and another routing protocol.
Table 7-14 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table 7-14 IP Enhanced IGRP: Routes Missing from Routing Table
Possible Problem Solution
Routers not establishing
neighbors
For information on troubleshooting this problem, see the section “IP Enhanced
IGRP: Routers Not Establishing Neighbors,” earlier in this chapter.
Routes are not
redistributed between
different autonomous
systems
Routes are not automatically redistributed between different Enhanced IGRP
autonomous systems.
Step 1 Use the show running-config privileged exec command on routers
bordering multiple autonomous systems.
Step 2 If multiple autonomous systems are configured on the router (indicated
by multiple router eigrp global configuration command entries), make
sure that route redistribution is manually configured using the
redistribute router configuration command.
For example, if the router belongs to autonomous system 100 and
autonomous system 200, enter the following commands to redistribute
Enhanced IGRP routes between the two autonomous systems:
C2509(config)#router eigrp 100
C2509(config-router)#redistribute eigrp 200
C2509(config-router)#exit
C2509(config)#router eigrp 200
C2509(config-router)#redistribute eigrp 100
Step 3
If you want static routes to be redistributed, you must use the redistribute
static router configuration command.
For more information on using the redistribute router configuration command, see
the Cisco IOS configuration guides and command references.
Routes are not being
redistributed between
different routing
protocols
Step 1 Use the show running-config privileged exec command on routers that
border networks running different routing protocols.
Step 2 Look for a redistribute router configuration command entry. Make sure
that routing information is being properly exchanged between protocols.
For example, to redistribute routes between IGRP autonomous
system 500 and Enhanced IGRP autonomous system 200, enter the
following commands:
C2509(config)#router igrp 500
C2509(config-router)#redistribute eigrp 200
C2509(config-router)#exit
C2509(config)#router eigrp 200
C2509(config-router)#redistribute igrp 500
Step 3
To redistribute static routes, you must use the redistribute static router
configuration command.
For more information on using the redistribute router configuration command, see
the Cisco IOS configuration guides and command references.