How to Open a Port in Ubuntu using UFW

Open a Port in Ubuntu using UFW UncomplicatedFirewall (UFW) is a command-line, frontend iptables manager, similar to Firewalld and ConfigServer Security & Firewall (CSF). It’s beneficial to understand basic UFW commands since it’s pre-installed with many Ubuntu-based operating systems (OSs) including Mint.

Those configuring UFW for a desktop system who prefer not to use the CLI can use the GUFW GUI application.

if you’re installing new server management software such as Apache or Webmin, you’ll need to ensure the appropriate ports are open.

Open a Port in Ubuntu using UFW

There are multiple ways to open a port in UFW. Below we cover how to open ports using the port number, service name, and custom IP/port combination.

• Log into SSH as root.
• Check if the application port is defined as a service (e.g. MySQL, OpenVPN, PostgreSQL, ):

cat /etc/services | grep service-name

or

cat /etc/services | grep port

To navigate the full list, use Page Up, Page Down, and arrow keys after using the less command:

less /etc/services

If the service is listed, you can open the port using the service name (TCP/UDP protocol optional):

sudo ufw allow servicename

sudo ufw allow servicename/tcp

If there is no service listed for the port, you can open the port by specifying the port and protocol (TCP/UDP):

sudo ufw allow 8000

sudo ufw allow 1652/udp

If you need to allow all connections from a specific system or network IP address:

sudo ufw allow from 10x.14x.11.12x

To allow all connections from a specific IP subnet:

sudo ufw allow from 10x.14x.11.12x/24

To allow connections on a specific port from an IP address:

sudo ufw allow from 10x.14x.11.12x to any port 22xx

After you open a port in UFW, ensure UFW is enabled:

sudo ufw enable

Close a Port in UFW

After you uninstall software you should close any ports you no longer need open on your system. You can accomplish this using the service name or port number.

To close a port in UFW using the service name:

sudo ufw deny pop3

To close a port in UFW using the port number:

sudo ufw deny 110

Check Open Ports in UFW

After making changes to any firewall, you should verify your changes to ensure they’re correct and active.

To check whether UFW is running:

sudo ufw status

To check whether UFW is running with additional information such as logging and profile status:

sudo ufw status verbose

To find the rule number for UFW rules:

sudo ufw status numbered

Then you can remove the rule:

sudo ufw delete 1

From the above article we will know and understand how to Open a Port in Ubuntu.

To know about SSH Essentials: Working with SSH Servers, Clients, and Keys click here.