Husse wrote: OK, so you mean that (and specifically in Ubuntu based distros) you are safe because you don't run as root, unlike in Windows where everyone has administrator privileges.
To some degree and up to a certain part, yes. But there are many architectural differences too that make it way harder for any malware to infect a Linux machine in any way. Not that it is "impossible" ... I have read about people manipulating Linux kernels and installing key loggers ... but that's daft. Why? In order to install such a manipulated kernel you have to be root. To become root you have to hack your way into the machine. BUT: Once you're already root ... what's the point of installing a manipulated kernel which would spy on the other users when you are already blessed with God-like priviledges and can wreak havoc whatever way you wish and install backdoors galore, manipulate whatever you want whenever you want ... You see what I want to say? Under Linux you're rather at danger of getting your machine hacked by a knowledgable human with possibly (but not necessarily) evil intentions (there are "ethic" hackers too!) rather than some stupid VBscript a 15-year old bored teenager came up with because Windows has so many security flaws inherent to the way it was designed ...
Husse wrote: I'm a bit "paranoid"
Welcome to the club
Husse wrote: Your answer indicates to me that to get Firestarter up and running is essential
If you're running services a firewall (not necessarily "Firestarter" ... there are many more options!) definitely helps. But it's just part of the process, a firewall is not the answer to all problems. A firewall doesn't help if you leave port 80 for HTTP traffic to your web server open and a knowledgable hacker finds ways to exploit stuff you have on your web page (that's a typical attack route! e.g. badly secured PHP or PERL / CGI scripts that are accessible from outside and can be manipulated to do things they were not meant to do ... !)
Besides: At the same time this is valid too: No serves = in most cases no need for a Firewall! Why? Because if you don't run any services then there is nothing a potential intruder could try to exploit, and therefore there is nothing that would require this form of protection. This is another difference from Windows which is always running some stupid network service in the background even if you tell it not to! -- hence the need even for Windows home users to always keep the firewall running or else they are in for a really bad surprise ...
I've learnt since then, though...
