Investigating Routing Problems

As networks evolve, I find that some IT teams overlook routing issues. Their attitude is "if it ain’t broke, don’t fix it." Routing problems don’t necessarily result in dramatic outages, so IT teams are apt to ignore them.

When troubleshooting suspected routing issues, the obvious first step for a network analyst is to perform a trace route from his or her computer. However, results will vary, depending on where you investigate the problem.

In this video, I show the various results I got when troubleshooting a routing issue.

I recommend performing the traceroute from the client's subnet, computer, or better yet from any layer 3 (or higher) device. Don’t be fooled by a layer 2 switch since many of the corporate class switches can route as well.

Different types of routing protocols behave differently. The protocol will influence how you approach troubleshooting routing issues.