The following commands are used to troubleshoot basic IP (L3) connectivity issues:
- “show” commands
The ping commands which stands for packet internet groper. It sends raw ICMP packets and is the most common use or testing links as it tests traffic it both directions.
The various trace route commands show the hops that a IP packet takes on route to it’s destination.
“show” commands such as “show ip route” on IOS or “route show” on FreeBSD are useful for finding L3 problems due to incorrectly configured or missing routes.
If you follow the examples in this blog you will have to use these commands during the exercises naturally. I think it is pointless to go through the commands without a context.