To change the default SSH port of your CentOS 7 server, the first thing you want to do is backup the current SSH configuration on your system.
To do that, run the commands below.
sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak
Above command creates a new named sshd_config.bak with the current settings of the sshd_config file.
If something goes wrong, you can then restore the file from this created backup.
Next, run the commands below to open the default SSH configuration file
sudo vi /etc/ssh/sshd_config
When the file opens, make the below change and save the file. Un-comment or remove the (#) before the line the reads Port and change the port number you want to use.
# If you want to change the port on a SELinux system, you have to tell # SELinux about this change. # semanage port -a -t ssh_port_t -p tcp #PORTNUMBER # Port 2244 #AddressFamily any #ListenAddress 0.0.0.0 #ListenAddress ::
Save the file.
After saving, don’t exit until you’ve completed these steps.
By default, SELinux only allows port 22 for SSH. What you need to do is enable the newly created port through SELinux. To do that, run the commands below
sudo semanage port -a -t ssh_port_t -p tcp 2244
If you run the commands above and get an error that semanage command not found, run the commands below to install it.
sudo yum -y install policycoreutils-python
Then go and run the semange commend again to allow the new port through SELinux.
After that, run the commands below to allow the new port through the firewall.
sudo firewall-cmd --permanent --zone=public --add-port=2244/tcp
Reload the firewall configurations
sudo firewall-cmd --reload
Restart SSH by running the commands below.
sudo systemctl restart sshd.service
Verify that SSH is now running on the new port by running the commands below.
ss -tnlp | grep ssh LISTEN 0 128 *:2244 *:* users:((“sshd”,10783,3)) LISTEN 0 128 :::2244 :::* users:((“sshd”,10783,4))
Exit and try signing in using the new port number.
ssh firstname.lastname@example.org -p 2244
That’s it we are done!
Want to know how to change the open SSH port of other Linux OS versions? Then check our other article at http://www.xeonbd.com/changing-the-ssh-port-xeonbd-blog/