Troubleshooting IGRP Routes Advertisement

All these problems discussed so far deal with a problem on the receiving end or a problem in the middle (Layer 2).

There is a third possibility for why the route is not being installed in the routing table ‚ the problem is occurring on the sender's end. The sender might be having a problem sending IGRP updates, so the receiver is not installing the IGRP routes in the routing table. This next section talks about the things that can go wrong on the sender's side.

This section discusses the most common scenarios that can prevent IGRP routes from being advertised out. Some cases overlap with IGRP route installation problems ‚ for example, missing network statements and downed interfaces. This section assumes that you did troubleshoot all the possible scenarios discussed in the previous section and that the prob-lems still exist. In this case, the last place to look at is the sender.

This chapter covers two problems related to IGRP route advertisement originating from the sender's side:

• The sender is not advertising IGRP routes.

• The candidate default is not being advertised.