Is there anyone of seeing if anyone is hacking your computer

Question

I have a firewall on my router, Netbarrier and Leopards built insystem all working but I still wonder if anyone is accessing my computer.
My apple firewall log shows numerous Stealth Mode connection attempts.
So how do you know if someone is actually getting in or not?

Answer 1

Yep, way too much TV - liberties are taken with pretty much any technology in order to make a plot (or what passes for a plot these days) work, and "hackers" are a prime target.
A router is specifically designed to route traffic from one network (e.g. the internet) to another (e.g. your local network). Unless set up to do so, some random connection from the outside world (and yes, there is a constant barrage) will not get routed to anything in your local net. That's not to say there isn't a bunch of traffic from services you may not be aware of, such as from various items on the web page you are visiting, domain name services, time servers, synchronization services, etc. All of that traffic is generated by you (or the system via your settings) though, so a log entry doesn't necessarily mean something bad.
If you are running in a standard (non admin) account, use decent passwords, are behind a router and a couple of firewalls, and don't specifically install anything you don't know about, there isn't much chance that someone is going to be able to hack into your system. Anything is possible I suppose, but no one is going to waste their time trying to hack into a system with locks on all the doors - there are plenty of people that leave the upstairs window open (so to speak).