A backdoor is basically a very generic term for a way for an intruder to get in to another system. It can work in a number of ways, either being left in code, or a trojan, etc. Well, you last question is a little tougher. If the backdoor is a trojan, then chances are it will show up on a virus scan. But if it is embedded in the code of a legitimate app (wasnt there one in redhat a couple years ago, pirhana or something?) then you might have a problem, because it will be a little harder to find. Google it. Sorry, i gotta go to school.


slick