Need of a firewall

[best63]

):P

Hello, I'm a new person to Ubuntu, this OS is just Great! I have installed the clamav antiVirus software. How important is it to have a firewall. I do have firewall on my router. Looking at what it takes to install the firewall I could get in trouble configuring it.
Thanks for your help.

[bodhi.zazen]

First, welcome to the Forums.

Since you are asking a general question :

Ubuntu Security - Ubuntu Forums (http://ubuntuforums.org/showthread.php?t=510812)

In general you do not need antivirus or a firewall, but if you read that thread you will know where to start.

If you want a slightly more technical overview of your firewall,

http://bodhizazen.net/Tutorials/iptables/