Ubuntu – Does Ubuntu come with a firewall by default

firewallgufwSecurityufw

I have been told that Ubuntu comes with the firewall UFW. Is this true? Is there a GUI for it? If so, what is its name and where do I download?

Is it possible for UFW to notify us (like in windows with a pop-up window) when someone wants to access to your PC or when an application wants to access the internet?

If not, is there any firewall for Ubuntu that provides such notifications?

Best Answer

Yes Ubuntu has a firewall installed by default.

The Firewall in Ubuntu is iptables Wikipedia. It also comes with an easy to use command line frontend called UFW Wikipedia (Uncomplicated Firewall).

If you want to change any settings, you can use the graphical front end to that command line front end, GUFW Install gufw

alt text

As for your other question, getting a warning when an application connects to the internet:

I don't know of any programs that do this*, but I have written one. Now, this isn't great quality software - it's a quick hack in fact -but it works all right. You'll notice I haven't packaged it in any way, because I don't have any use for it and I don't think its tested well enough to be deployed on Anything That Matters™

It doesn't even have a name, here's how it looks:

alt text

(ignore the German captions, they will be in your local language)

And here's how to use it:

  • Install Python 3 Install python3

  • download it and save it as a file on your computer

  • Via the file properties, mark it as executable

  • Double click and choose "Run"

The program will issue a warning for every application that tries to access the internet. It will not prevent it from doing so, but it'll let you know. You then have the option of putting it on a "White List" of trusted applications, which causes it to not warn you again about this particular program.

If you start it from a terminal, you'll get a few useful messages about what it's doing.

Again I have to stress, even though it works, I haven't tested it properly (i.e. with many users trying it out).

For the purposes of support, you may send me email about it, I don't mind

* It seems UFW is able to do it!

This section is really better suited for someone managing servers than for desktop users:

UFW comes with an Application Filter. It's configuration is a simple text file at /etc/ufw/applications.d.

To get a list of all the application filters, type

sudo ufw app list

Which should look like this:

Available applications:
  Apache
  Apache Full
  Apache Secure
  CUPS

To get more details on any one application, type - for example:

sudo ufw app info 'Apache Full'

More details are available in the relevant Ubuntu help wiki page

As for the question of default configuration: By default, Ubuntu ships with no open ports on public interfaces
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