How To Setup UFW Firewall on Ubuntu and Debian

Written by Rahul, Updated on July 31, 2019

UFW (Uncomplicated Firewall) is a front-end for iptables firewall. It’s well-suited for host-based firewalls. It is designed to provide an easy for managing firewalls, even the user does not have many ideas about firewalls. This tutorial will help you to set up UFW for firewall on Ubuntu and Debian Systems.

Install UFW

First, make sure you have installed the latest version of UFW firewall on your Ubuntu system. Use the following command to install or update the UFW firewall.

sudo apt-get update
sudo apt-get install ufw

Enable/Disable UFW

Use following commands to enable or disable firewall.

Disable UFW

sudo ufw disable

Enable UFW

sudo ufw enable

Check UFW Status

Now make sure ufw is in active mode.

sudo ufw status

Status: active

To                         Action      From
--                         ------      ----
22                         ALLOW       Anywhere
22 (v6)                    ALLOW       Anywhere (v6)

Enable/Disable IPv6

You might be required to use IPv6 with your firewall. Disable IPv6 support if your system is not configured to use IPv6. To do it edit /etc/default/ufw and set IPV6 “yes” or “no”.

IPV6=no

After making changes disable and enable firewall

sudo ufw disable && sudo ufw enable

Allow Connections with UFW

Allow Specific Ports – To allow a single port, for example allow port 21(FTP), 80(HTTP) and 443(HTTPS).
```
sudo ufw allow 21/tcp
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
```
Allow Specific Services – UFW uses /etc/services files to get port of specific service, So we can allow any service with name instead of defining port. Like ftp (21), http(80).
```
sudo ufw allow ftp/tcp
sudo ufw allow http/tcp
sudo ufw allow https/tcp
```
Allow Port Range – We can also allow range of ports in single command like:
```
sudo ufw allow 1100-1200/tcp
```
Allow Access to Specific IP – To allow connections from specific ip address use following command.
```
sudo ufw allow from 192.168.1.100
```
Allow Access to Subnet – To allow connections from any ip address of subnet use following command.
```
sudo ufw allow from 192.168.1.0/24
```
Allow IP to Specific Port – To allow connections from any ip address of subnet use following command.
```
sudo ufw allow from 192.168.1.100 to any port 22
```

Deny Connections with UFW

Deny Specific Ports – To allow a single port, for example allow port 21(FTP), 80(HTTP) and 443(HTTPS).
```
sudo ufw deny 21/tcp
sudo ufw deny 80/tcp
sudo ufw deny 443/tcp
```
Deny Port Range – We can also allow range of ports in single command like:
```
sudo ufw deny 1100-1200/tcp
```
Deny Access to Specific IP – To deny connections from specific ip address use following command.
```
sudo ufw deny from 192.168.1.100
```
Deny Access to Subnet – To deny connections from any ip address of subnet use following command.
```
sudo ufw deny from 192.168.1.0/24
```
Deny IP to Specific Port -To deny connections from any ip address of subnet use following command.
```
sudo ufw allow from 192.168.1.100 to any port 22
```

Enable or Disable Logging

UFW created logs for all filtered connections in /var/log/ufw.log file. It can be helpful for troubleshooting Use below to To enable or disable logging.

Enable logging:

sudo ufw logging on

Disable logging:

sudo ufw logging off

Reference: https://wiki.ubuntu.com/UncomplicatedFirewall

1 Comment

Anders Reply
June 26, 2016 at 2:07 am
Please do not remove the support for IPv6.
That will bite you hard if you connect to a network that supports IPv6.
If you have support for IPv6 turned on, It will not be used if you don’t have support for IPv6 routing in your machine or network. And it will protect you if you have it added. Iven if you turn off the IPv6 module.
So please, remove or at least strongly suggest not to turn of UFW support for IPv6, even id your machine/network doesn’t support IPv6 for some strange reason.