I havn't attended the School of Hard Knocks WRT intranets (or at least intrawebs). However, one thing to remember: Never authenticate based on what wire you're sitting on. By this I mean that you should never assume somebody is a legitimate number of your compony because they've established an Ethernet connection on your local network. I say this because of two reasons. First off, there's network jacks in the waiting room that you hadn't noticed behind that fake shrub. Secondly, there will be a day when that "wire" is a RF frequency.

Always authenticate before you give out any data you wouldn't give to anybody who came up to your reciptionist (or local eqiv) and asked.