View source for Configure UFW to manage Docker related connections

==Prologue==
This guide applies to Ubuntu 20.04. After you installed docker and setup UFW to block all connections by default, docker will bypass the firewall entirely.

=== /etc/docker/daemon.json===

Start by creating/editing following file: <code>/etc/docker/daemon.json</code><syntaxhighlight lang="json">
{
"iptables": false
}
</syntaxhighlight>

=== /etc/ufw/after.rules===
Then you need to edit following file as well: <code>/etc/ufw/after.rules</code>

Make sure to paste following lines '''before''' the last line in the file which is <code>COMMIT</code>

Also adjust <code>ens3</code> to your default interface name.<syntaxhighlight lang="md">
# Put Docker behind UFW
*filter
:DOCKER-USER - [0:0]
:ufw-user-input - [0:0]

-A DOCKER-USER -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A DOCKER-USER -m conntrack --ctstate INVALID -j DROP
-A DOCKER-USER -i ens3 -j ufw-user-input
-A DOCKER-USER -i ens3 -j DROP
# End Docker UFW rules
</syntaxhighlight>Once you've done this, execute following commands to apply your changes:
{{warning}} This will restart all your docker containers.

<code>sudo systemctl restart ufw</code>

<code>sudo systemctl restart docker</code>

Test your configuration to make sure the changes are working.
[[Category:UFW]]
[[Category:Docker]]