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- In this video we'll talk about UFW.

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So UFW is Uncomplicated Firewall,

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and it was developed to work
with an intuitive syntax.

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You use it on Ubuntu. Let's check it out.

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So here we are on the Ubuntu server,

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and I'm using sudo ufw status,

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where we can see it's inactive.

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Well, I want it to be active.

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So enable,

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and now it is active.

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So if we do a status again,

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we can see it is active.

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So next we are going to
specify what we want it to do.

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sudo ufw allow ssh.

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Oops, that was a typo.

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And now the rule is added
for IPv4 as well as IPv6.

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And we have allow, we can also use reject.

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And I'm using reject out ssh.

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So that means that we
do allow incoming SSH,

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we don't allow outgoing SSH.

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Next I'm using sudo ufw status,

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and we can see exactly what is going on.

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So let me use

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sudo ufw delete reject out ssh.

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That is what you do

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if you regret that you've done something.

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Now, we can also do
more complicated stuff,

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like sudo ufw deny proto tcp
from 10.0.0.10 to any port 22.

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So that means that anything
coming from 10.0.0.10,

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a specific host,

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is not allowed on any
network card port 22.

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We can verify that using sudo ufw status,

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and there we can see the DENY
line that is nicely listed.

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So sudo ufw reset

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will reset everything.

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That is your "I'm desperate" option,

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and that's easy if you wanna get out.

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Now UFW also works with apps.

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You can use services.

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When we use sudo ufw allow ssh,

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it uses a service,

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and that corresponds to the
service names in /etc/services.

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Now I'm going to use sudo ufw app list.

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Oops, ufw.

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And there we can see that it has

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the amazing amount of
one application, OpenSSH.

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Well, as we only have one application,

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I'm bound to using that.

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sudo ufw app info OpenSSH.

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The applications that you've got

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depend on the packages
that you have installed.

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And on the slide you can see Samba.

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I don't have Samba installed,

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so I also don't have the application.

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Now if I use sudo ufw logging on,

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that's what we can use to enable logging.

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And finally if you want to know more,

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man ufw.

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It has a man page,

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and in that man page you
will find the rule syntax,

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containing some examples,

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and it's a pretty big man page,
and hopefully it's helpful.

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That's all I wanted to tell you about UFW.