90 - 238 CCNA 2: Routers and Routing Basics v3.1 Instructor Guide – Module 7 Copyright © 2004, Cisco Systems, Inc.
the networks advertised, timer values, and other routing protocol-specific information. The
show ip route command displays the routing table and lists the next hop to all known
networks, how the route was learned, the metric, and other route specific information. The
show run command can be used to verify the running configuration. Have the students verify
proper operation of IGRP on the lab topology.
7.3.8 Troubleshooting IGRP Most of the IGRP configuration errors involve a bad network statement, discontiguous subnet,
or incorrect autonomous system number. The following commands are used to troubleshoot
IGRP:
• show ip protocols
• show ip route
• debug ip igrp events
• debug ip igrp transactions
• ping
• trace
Both the debug ip igrp events and debug ip igrp transactions commands can
be used to verify that routing information is being passed between routers. The ping
command can be used to test network connectivity. The trace command can be used to
locate pinpoint delay or connectivity issues. Have the students take a break and place several
IGRP problems on the lab topology. When the students return from the break, instruct them to
troubleshoot the topology and correct any problems they find. Emphasize the fact that the
show run command, which makes it easy to troubleshoot problems in a lab, may not be very
effective in real situations. The show run command should be used to verify configuration
changes.