Suse Firewall configuration& related questions
 

I'm quite new to Suse, and I didn't bother to configure my firewall in detail. Basicly I used the commands in Yast to deny every protocol I don't use, and I never had any problems with my system for over 6 months. But I decided it was time to learn more.

My questions are about configuring the Firewall:
1. How do I block an IP? If I don't want it to either be able to access my computer, and neither my computer to be able to access it.
2. How do I block a program? From what I understand, the default Suse Firewall blocks only protocols, not programs. But still, is it possible? Can I make it ask me as an annoying Windows firewall, what programs I want to allow to access the internet and which not?
3. Every security problem, hack attempt, and all is logged in various files, but can I make the Firewall notify me somehow when it happens?
4. What service do programs such as dc_qt and bit torrent use? What ports? What threats appear when I allow that service? Any other info would help here.
5. How do I know what ports are opened, what ports are used and how can I open/close them?

That's about the basic info I need, the rest I will find in various Linux books I am reading, but I need to get started somehow.

And I would also like to ask about this thing I frequently find in my system log:
Jul 24 14:27:22 (*my ip*) kernel: martian destination 0.0.0.0 from (*other IP, sometimes from the same prvider as mine*), dev eth0

What is "martian destination? what is "eth0"? Why do these appear?

More questions soon, if someone could please answer this set. Thank you for any info related to the subject, and sorry if there is a similar topic, but I could not find anything either searching on the forum, or in the tutorials on the site.