Minimal UFW Setup
UFW (Uncomplicated Firewall) is a firewall software package that is easy to use initially and yet flexible enough for power users.
Install ufw if it not already installed,
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sudo apt-get install ufw # install the firewall software |
UFW once installed does not automatically start. First open up ports that are necessary for the administration of the system,
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sudo ufw allow 22 |
Additionally open other ports that you require. For this tutorial it would be,
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sudo ufw allow 80 # Web Server
sudo ufw allow 443 # SSL over Web Server |
Before starting UFW make sure you have port 22 open you can check again by running the allow 22 command again and if the rule is added should output.
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sudo ufw allow 22
"Skipping adding existing rule" |
After you have confirmed 22 is open you can go ahead and enable UFW.
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sudo ufw enable |
Finally check that all your rules are in place,
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sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing)
New profiles: skip
To Action From
-- ------ ----
22 ALLOW IN Anywhere
80 ALLOW IN Anywhere
443 ALLOW IN Anywhere |
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UFW status verbose will not work if UFW is not enabled. |
There is much more to UFW but the above steps should get you going.
More UFW Commands
Here are some more useful ufw commands,
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sudo ufw deny 443 # Disables and leave the entry in the status. Useful for a port you leave on and off sometimes.
sudo ufw delete allow port 443 # Actually delete the firewall rule entry. Note you must have it enabled to delete it. |
Article Improvements
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This article can be improved in the following areas. |
How I can put comments in the firewall rules and have it show up in the ufw status? Using applications.d. Will add details from here,http://manpages.ubuntu.com/manpages/jaunty/en/man8/ufw.8.html
Do you really need to enable the port to delete it? That was the only way the command worked for us, but then again we might have to use a different syntax for deleting a disabled port.
References
https://help.ubuntu.com/9.10/serverguide/C/firewall.html - official docs from Ubuntu.