Denne nyttige guiden fant jeg her . Den er på engelsk, men hvorfor ikke :) A new Ubuntu Server install (as of 10.04) contains a firewall ( iptables ) that is not enabled. Ubuntu.com has a great tutorial that explains that ufw is the default configuration tool for iptables. After I set up my server, I used ufw to close all ports by default, then open up ports for the services I use. I don’t have complex security needs or run a proxy server, so my rules are simple. Adding Rules Before adding rules, it’s best to explicitly set the default behavior. By default, I like to block everything: both incoming and outgoing traffic. After that is done, I selectively open ports to support the services I wish to run. In contrast, UFW, by default, denies all incoming traffic but allows all outgoing traffic. That setup is accomplished manually with the following commands. $ sudo ufw default deny incoming $ sudo ufw default allow outgoing The following commands open ports for named services tha...
"A lie told often enough becomes the truth" – Lenin