Changing the SSH Server Port Number

By default, SSH servers listen on port 22. For security reasons, or when required by third-party services, you may want to change this port number. This guide explains how to safely update the SSH port on your Server.

Steps to Change the SSH Port

Step 1: Log in as Root

Connect to your server using SSH on the current port (default is 22):

ssh root@yourdomain.com -p 22

Step 2: Edit the SSH Configuration File

Open the SSH configuration file in a text editor:
```
nano /etc/ssh/sshd_config
```
Locate the line:
```
Port 22
```
Change 22 to your desired port number (e.g., 7822).
```
Port 7822
```
Save and exit the file.

Step 3: Update Firewall Rules

If your server has a firewall enabled, you must allow the new port:

iptables example:

iptables -A INPUT -p tcp --dport 7822 -j ACCEPT
service iptables save

firewalld example (CentOS/AlmaLinux):

firewall-cmd --permanent --add-port=7822/tcp
firewall-cmd --reload

ufw example (Ubuntu/Debian):
Terminal window
```
ufw allow 7822/tcp
ufw reload
```

Step 4: Restart the SSH Service

Restart SSH to apply the changes:

On AlmaLinux/Fedora:
Terminal window
```
service sshd restart
```
On Debian/Ubuntu:
Terminal window
```
service ssh restart
```

Step 5: Test the New Port

Open a new terminal window and try connecting with the new port:

ssh root@yourdomain.com -p 7822

Do not close your original session until you confirm the new connection works.