Network unavailable after start up

There is a FreeBSD machine which normally has a network connection, but after a recent start up no longer has such a connection. All other computers on the same router do have an active network. Where do I start looking to troubleshoot this?

Thanks in advance

I would log in at the console and start looking at the syslogs, then check ifconfig and/or netstat, etc. Perhaps see if there is a low level link by looking at the blinking light next to the nic.

Thank you for your answer and the problem has solved itself somehow.