I am a novice at Ubuntu (12.04). I have it on my netbook which I use mainly for surfing the net, learning python and remote desktop into my work computer.

Do I need to enable a Firewall type software? If so, what would you suggest, and what are sensible default suggestions?


In most desktop cases you don't need to have a firewall. When you use a router at home, it does already quite a job -- for example, it does network address translation (NAT) such that you only have a local IP -- not reachable from the Internet.

Also, Ubuntu does not open any ports out of the box, so that there is no real danger of anyone trying to hack into your SSH.

Finally, all firewalls actually are different interfaces to the same thing -- the iptables of the Linux kernel.

You really need a firewall if your machine sits in a LAN, with an IP visible for the whole world and you need to open up some ports (for example, you run a server, be that a test web server installation or an SSH server).

Furthermore, a firewall is very useful if you want to limit which addresses are allowed to use an open port on your machine (e.g. you only allow the IP of your lab workstation to connect to the SSH port of your home computer).

Of course, you might want to learn iptables one day :-) However, in that case, learn the iptables and networking first, and then use one of the alternatives which make the life of a network admin easier.

  • Even if your computer is on an untrusted network running servers, it still might not need a firewall. Suppose you run an ssh server on port 22 (the default port for SSH). If your computer is connected directly to the Internet, not through a NAT router, pings and probes to ports other than port 22 will reveal they are closed (and thus that the computer is there). So arguably it's better to have a firewall that drops pings and unsolicited TCP traffic. But probes to port 22 will still reveal there's a server, just as with no firewall. Aug 21 '12 at 18:00
  • @January - thanks. Does using remmina to remote desktop cause any particular security issues if I'm on an untrusted network (e.g. at a coffee shop etc)?
    – Andrew
    Aug 21 '12 at 20:53
  • No idea, I guess that depends on the remote desktop protocol. Of course the issue here is the computer that you are trying to connect to. In general, vpn or ssh tunnel are advisable when at a coffee shop. In my lab, all workstations are kept behind a firewall and you need to use vpn to connect from outside.
    – January
    Aug 22 '12 at 4:59

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