Prior to posting this, did you actually take the time to search for the possible answers to your questions?, or did you just think , Lots of questions playing on my mind. Oh I'll post this on AO, save me the time and trouble to use my initiative and look for myself. ===>>> hint: Sygate, protocols, port Nos
Thanks for the hints jm459. I've been looking into and reading about firewalls, on and off, for a few years now. Granted i'm not doing a security course/degree and therefore i havn't had loads of time to search as deeply as i would have liked. These questions (mainy the one core one of how to firewalls actually find out about and monitor connections) have always bugged me, so i throught i'd ask on AO forums and see if they could help out in any way. I'm sorry if i offended or pissed you off by my post.

Thanks for the info nihi (you rock man). You say the firewall monitors incoming and outgoing traffic. Any ideas how it does this ? Does the operating system provide this service with sytem calls, or does it edit a device drvier etc ?