How can I tell if my network connection is working or not?

On the back of the server, front of switch, and/or back of the workstation/adapter, there should be link lights (green lights).  If there are no lights, that means there is a disconnect physically along the way.

A 169.xx.xx.xx address indicates there is a disconnect as well or an IP is configured incorrectly at either the workstation.  Physical connections must be checked.  Cables may need to be reseated (unplugged and plugged back in).