Examining Network Connections on Linux Systems
There are a lot of commands available on Linux for looking at network settings and connections. In today's post, we're going to run through some very handy commands and see how they work.
One very useful command is the ifquery command. This command should give you a quick list of network interfaces. However, you might only see something like this —showing only the loopback interface:
$ ifquery --list lo
If this is the case, your /etc/network/interfaces file doesn't include information on network interfaces except for the loopback interface. You can add lines like the last two in the example below — assuming DHCP is used to assign addresses — if you'd like it to be more useful.
Read more at NetworkWorld