Tuesday, May 13, 2008

HowTo: Uncomplicated Firewall (ufw) in Ubuntu 8.04

I've recently upgraded several of my systems to Ubuntu 8.04 (Hardy Heron). While poking around, figuring out what has changed since 7.10 (Gutsy Gibbon), I came across the 'ufw' command, which is an acronym for Uncomplicated Firewall.

Personally, on my linux systems I've preferred working with iptables directly. Several years ago I started using 'fwbuilder' to manage my iptables. Nonetheless, I'm still interested in playing around with ufw to see what value it has.

Here's an ifw example using OpenBSD's PF syntax:

  • Let's assume I want to allow all ssh traffic (22/tcp) from the subnet to my host at IP
sudo ufw allow from to port 22
  • Is there a single host that's bothering you and you want to block it?
sudo ufw deny from {IP address}
If you're interested in testing ufw, the Ubuntu Unleashed Blog [link] has a useful guide on using the tool. Of course, you can always use the man pages as well [`man ufw`].

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