Here's the situation. I'd like to get a lunchtime office game going, but sadly we're behind a corporate firewall so I can't use any Steam versions of HL.

Is it possible to use NS3.x?

If so, what Linux HL server version and Windows HL client versions would I need to use?

I realise this forum is pretty much dead so this is a long shot, but I figured it didn't hurt to try.