How to Open Ports in UFW on Ubuntu 26.04

UFW (Uncomplicated Firewall) allows Ubuntu administrators to manage firewall rules using simple commands. Opening specific ports is necessary for services such as websites, SSH access, databases, and game servers.

On a public Linux VPS server, correctly configuring firewall ports helps keep services accessible while reducing unnecessary exposure to the internet.

Step 1: Connect to the Ubuntu Server

Access the server using SSH:

ssh root@your_server_ip

Step 2: Check UFW Status

Verify that the firewall is installed and active:

ufw status verbose

If UFW is not installed yet, follow this guide to install UFW Firewall on Ubuntu before continuing.

Step 3: Open a Specific Port

Allow incoming traffic on port 80:

ufw allow 80/tcp

Example for HTTPS traffic:

ufw allow 443/tcp

The tcp protocol is commonly used for web servers, SSH, and application services.

Step 4: Open a UDP Port

Some applications use UDP instead of TCP.

Example:

ufw allow 53/udp

UDP is commonly used for DNS, voice services, and game servers.

Step 5: Open a Port Range

Allow multiple ports at once:

ufw allow 6000:6010/tcp

This is useful for applications requiring several ports simultaneously.

Step 6: Allow SSH Access

Ensure SSH connections remain accessible:

ufw allow OpenSSH

Or allow a custom SSH port:

ufw allow 2222/tcp

Incorrect SSH firewall rules can lock administrators out of the VPS server.

Step 7: Reload UFW Rules

Reload the firewall configuration:

ufw reload

Check the updated firewall rules:

ufw status numbered

Step 8: Remove an Open Port Rule

Delete a firewall rule by port:

ufw delete allow 80/tcp

You can also remove rules using their rule number:

ufw delete 1

Step 9: Verify Listening Services

Check which ports are currently active on the server:

ss -tulnp

This command displays active TCP and UDP listening services.

Properly managing firewall ports on Ubuntu 26.04 helps maintain server security while ensuring applications and public services remain reachable from external networks.