Change the SSH Port on Your Server | Hostvento Knowledge Base

What are SSH and ports?

SSH is a safe way to type commands on a server from your own computer. A port is like a numbered door on your server. Each service uses one door. SSH normally uses door 22. Attackers know this, so they keep knocking on it. Moving SSH to a different door cuts down on this noise. It is not full protection, so you should still use strong passwords or SSH keys.

Warning: A mistake can lock you out. Keep your current SSH window open until you test the new port in a second window. Also ask Hostvento support if your plan has an outside firewall that needs the new port opened.

Steps

Pick a new port number between 1024 and 65535. For example, 2222. Do not pick a port another service uses.
Log in to your server with SSH.
Open the SSH settings file.
```
sudo nano /etc/ssh/sshd_config
```
Find the line #Port 22. Remove the # and change the number.
```
Port 2222
```
Save the file. In nano, press Ctrl+O, Enter, then Ctrl+X.
Open the new port in your firewall. A firewall is a guard that decides which doors stay open. Use the command for your system.
```
sudo ufw allow 2222/tcp
```
That one is for Ubuntu with UFW. On CentOS with firewalld, use sudo firewall-cmd --permanent --add-port=2222/tcp and then sudo firewall-cmd --reload.
On CentOS with SELinux on, tell it about the new port.
```
sudo semanage port -a -t ssh_port_t -p tcp 2222
```
Restart SSH.
```
sudo systemctl restart sshd
```
On Ubuntu the service may be named ssh.
Do not close your first window. Open a new window and test.
```
ssh -p 2222 username@your-server-ip
```
If it works, you may close the old window. You can later close port 22 in the firewall.

If it fails

Use your still-open window to undo the change.
Check that the firewall allows the new port.
Contact Hostvento support if you are locked out.

Quick recap

Edit /etc/ssh/sshd_config and set a new Port.
Open the port in the firewall first.
Restart SSH and test in a new window.
Connect with ssh -p from now on.