I am a Windows user trying to convert to Linux (Ubuntu), and I'm looking for alternatives to my Windows applications. I am looking for the Linux alternative to the user friendly personal firewall ZoneAlarm (in Windows).

ZoneAlarm is restricitve by default, and asks me each time a new application attempts to access the Internet, if it should be allowed to or not. No application can access the net without my knowledge and approval. This is the most important feature.

Example: I have two different music players installed. I want to allow only one of these to access the net (to fetch CD-info over port 80). The other one should never be allowed to access the web by itself.

How can I do this in Linux?

If it is impossible - why?

EDIT: Moderators feel free to move this post to "software" if the Security forum is geared towards server usage. What I am looking for is a personal desktop firewall.

Linux uses, at the heart of it's firewalls, IPTables. You can, if you have the knowledge (and the link should help there) hand configure your firewall. However, for those of us who need it, GUI frontends are available - Guarddog and Firestarter are both very popular and usable.

Welcome to LQ

TuxGuardian - An application-based firewall
http://tuxguardian.sourceforge.net/

Probably does what you want.

Yes, this does seem to offer a similar functionality to ZoneAlarm.

What worries me is that it is not available in the Ubuntu software repositories. Until now I've found absolutely everything there. Weird. I do not want to install experimental or unsupported/abandoned stuff that might force me to debug or reinstall my system at the next kernel upgrade or whatever.

I'm very interested in opinions of actual daily users of TuxGuardian:
Does it work without problems? What Linux distribution do you use it with?