This chapter discusses methods for troubleshooting various EIGRP problems. The flow-charts presented for each category of problems give you good direction on the trouble-shooting path. When doing a debug on the router, keep in mind that any debug has the potential to overwhelm the router, and the debug must be done when the router has low CPU utilization and preferably during a maintenance window. A great deal of the trouble-shooting can be done by just doing the show commands, as pointed out in this chapter. Take the time to understand the details of the output of the various show commands introduced. This way, when the problem happens, you can quickly and swiftly identify the problem and fix it.