What Is SSH Port Change?
SSH port change is the process of modifying the default port used for SSH remote connections.
By default, the SSH service listens on port 22. Since this port is widely known, it is a common target for automated attacks.
Why Change the SSH Port?
Changing the SSH port is a basic security measure. While it does not fully secure a server, it significantly reduces automated attack attempts.
- Reduces brute force login attempts
- Prevents unnecessary log file clutter
- Limits unauthorized access attempts
Things to Consider Before Changing the SSH Port
Before making any changes, ensure that your current SSH session remains open. Incorrect configuration may result in loss of server access.
You should also make sure the new port is allowed through the firewall.
How to Change the SSH Port
The SSH port is configured in the SSH daemon configuration file:
/etc/ssh/sshd_config
Locate the following line:
Port 22
Change it to a custom port, for example:
Port 2222
After saving the file, restart the SSH service:
sudo systemctl restart sshd
Connecting After Port Change
After changing the port, you must specify the new port when connecting:
ssh -p 2222 user@server_ip
Is Changing the SSH Port Enough?
No. SSH port change alone is not sufficient for full security.
It should be combined with additional measures such as:
- Disabling root login
- Using SSH key authentication
- Restricting access via firewall rules
From a knowledge base perspective, changing the SSH port is a fundamental but essential security step.
