How do I make sure I'm connected to other hosts?

Use the ping utility to determine if you're connected to other hosts.

For example:

ping isp.com

On success, ping displays something like this:

PING isp.com (10.0.0.1): 56 data bytes
64 bytes from 10.0.0.1: icmp_seq=0 ttl=255 time=0 ms
64 bytes from 10.0.0.1: icmp_seq=1 ttl=255 time=0 ms
64 bytes from 10.0.0.1: icmp_seq=2 ttl=255 time=0 ms
64 bytes from 10.0.0.1: icmp_seq=3 ttl=255 time=0 ms
64 bytes from 10.0.0.1: icmp_seq=4 ttl=255 time=0 ms
64 bytes from 10.0.0.1: icmp_seq=5 ttl=255 time=0 ms
64 bytes from 10.0.0.1: icmp_seq=6 ttl=255 time=0 ms

This report continues until you terminate ping, for example, by pressing CtrlC.