Hi.
Im new at this group and I have a question .
What Is the best antivirus and Firewall in linux ?! :-\
Thank you for answering.
Any particular reason you need AV and a firewall ?
If you are behind a NAT router, and you aren’t talking about a Linux server that serves files to Windows machines (so you want to scan the files for Windows viruses before passing them to the Windows PC’s) you don’t need AV … nor do you particularly need a firewall (unless this is something like a webserver).
What is the PC used for ?
and
Are you behind a NAT router ?
They ARE available, but for an average home PC, you don’t need them in Linux … and don’t let anyone tell you otherwise 
If you want to know WHY you don’t need them … read this posting and the 2 links at the bottom of it:
http://linuxforums.org.uk/index.php?topic=112.msg182#msg182
And this one if you’re interested:
http://linuxforums.org.uk/index.php?topic=3002.msg27132#msg27132
Mark forgive my lack of computer knowledge but what is a NAT router?
NAT = Network Address Translation:
Take it from me, if your router has more than 1 port for ethernet cables, and/or wireless … it’s a NAT router 
Ubuntu supplies a free firewall called firestarter. I downloaded it because its free, but I don’t know if I really need it and don’t know why its available for general distribution if its not essential. Should I get rid of it or just keep it as a safeguard ?.
You might want to see the first paragraph here:
https://help.ubuntu.com/community/Firestarter
I have taken firestarter off though it is still orffered as a free download.
A firewall is pretty much unnecessary for a Linux home PC if it’s behind a NAT router … unless of course you have some need to apply rules to outgoing packets, or want to say block something on your internal network.
Besides which, your router probably also has a built in firewall.
But if you really feel the need … as SeZo says, use gufw:
sudo apt-get install gufw
–
OK, the OP did not specify PC or Laptop. If it is the latter, then I would definitely recommend some sort of firewall.
Unlike with the virus checkers, there is a case for running some form of firewall in Linux.
I suppose it may be worth it if you regularly connect to public networks such as wifi hotspots… but then you’re not “behind” a NAT router … you’re on the same side as some other untrusted PC’s
My main computer is not on a router. Does that make it of more risk ?
How do you connect to the web then ?
It is connected directly by cable it has no Wi-Fi. The lap tops and notebooks are connected by router
Just because you are not using the WiFi does not mean that it is not connected via the router.
Is it connected to your router via the Ethernet cable or have you got a separate modem which connects to the web?
If you have, get rid of it “right now” … go on, find your bin and chuck it in … preferably hit it with a hammer a few times first
you REALLY need to be behind a NAT router
Is this the box the internet provider gives a client when they join?
Yes, the one that plugs into your phone line (via a splitter filter), and probably has 4 other ethernet sockets on the back.
So if you are using a mobile phone as the router how does that fit in with nat?
Just curious, don’t want to go off topic but phones are being used more often.
You should be running gufw and have blocked incoming connections.