This is a question about how Ubuntu (possibly) works, not help configuring anything.
I have a machine with Ubuntu 13.04 installed only. I used 'Startup Disk Creator' on said machine to copy an Ubuntu 13.04 image onto an USB stick.
Whilst "trying Ubuntu", booted from that stick on the same machine, I'm pretty sure it connected to my router without me having to provide any information. Does Ubuntu Live USB automatically pick up config information from the hard drive if there's already an Ubuntu installed? Or something else must have happened? If so, what types on configuration, and is there documentation specifying this behavior?