Linux Administration Cookbook

Checking connectivity

Just knowing what device our box is using as its gateway is one thing, but actually being able to reach it is another thing entirely.

If you're standing before a box, there's a good chance you've been summoned to try and work out what's not working. Trying to ping the gateway is a good first step:

$ ping 10.0.2.2PING 10.0.2.2 (10.0.2.2) 56(84) bytes of data.64 bytes from 10.0.2.2: icmp_seq=1 ttl=64 time=0.768 ms64 bytes from 10.0.2.2: icmp_seq=2 ttl=64 time=0.333 ms64 bytes from 10.0.2.2: icmp_seq=3 ttl=64 time=0.637 ms

Here, our gateway device responded, but if yours doesn't, or you get Destination Host Unreachable, then there's a good chance something is going wrong (or you've been given duff information by your colleague ...