If you implement static or dynamic routing or bridging on your network, at some point you are likely to encounter a situation that will put your troubleshooting skills to the test. We will first consider how to troubleshoot issues with routing.

The pfSense routing table is often a good place to start troubleshooting routing issues (under Diagnostics | Routes). Here, you can learn what routes exist, how they are configured, as well as how many times the route has been used. The table is divided into two sections (one for IPv4 traffic, and the other for IPv6 traffic. There are also several columns in the table. Some of the parameters in these columns are obvious, such as Destination, Use (which is the number of times a route was used), and Mtu (which is short for maximum transmission unit).

There is also a column called Flags; some of the more significant flags include...