Change SSH Port on CentOS 8

Change ssh port on centOS 8; Through this tutorial, we will learn how to change ssh port on centOS 8.

SSH or Secure Shell is a network communication protocol that enables two computers to communicate (c.f http or hypertext transfer protocol, which is the protocol used to transfer hypertext such as web pages) and share data.

Change SSH Port on CentOS 8

Follow the following steps to change ssh port on centOS 8:

• Step 1 – Backup Current SSH configuration
• Step 2 – Change SSH service port
• Step 3 – Allow new SSH port on SELinux
• Step 4 – Open SSH port on Firewalld
• Step 5 – Restart sshd service
• Step 6 – Verify SSH Service

Step 1 – Backup Current SSH configuration

First of all, open ssh and execute the following command into it to take backup of current ssh daemon configuration file:

date_format=`date +%Y_%m_%d:%H:%M:%S`
sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config_$date_format

Then execute the following command on terminal to verify backup of current ssh daemon configuration file:

$ ls /etc/ssh/sshd_config*
/etc/ssh/sshd_config  /etc/ssh/sshd_config_2022_07_06:22:40:10

Step 2 – Change SSH service port

Now, execute the following command on command line to open SSH service configuration file:

sudo vi /etc/ssh/sshd_config

Now the file has been opened with the above-given command. Search #Port 22 in that file:

#Port 22

Now remove # from this line and enter any port. We will put port 33000 in it:

Port 33000

Save the changes and close the file.

Step 3 – Allow new SSH port on SELinux

If we will see that now the label of the default port is. is what it was before. can see by executing the following command on terminal:

$ semanage port -l | grep ssh
ssh_port_t                     tcp      22

If we want to allow ssh to bind to the network port configured, then we need to execute the following command to modify the port type t ssh_port_t:

sudo semanage port -a -t ssh_port_t -p tcp 33000

Like now we have added the new port. We can use the command given below to verify it:

$ semanage port -l | grep ssh
ssh_port_t                     tcp      33000, 22

Step 4 – Open SSH port on Firewalld

Now the port we have added. For that we also need to do firewall configuration.

So execute the following command on terminal to allow firewall configuration for above-added port:

sudo firewall-cmd --add-port=33000/tcp --permanent
sudo firewall-cmd --reload

If Firewalld is not installed, use yum to install it and start the service:

sudo yum -y install firewalld
sudo systemctl enable --now firewalld
sudo firewall-cmd --add-port=33000/tcp --permanent
sudo firewall-cmd --reload

Step 5 – Restart sshd service

Finally, execute the following command on terminal to restart the ssh service for the make changes effect:

sudo systemctl restart sshd

Step 6 – Verify SSH Service

Finally, we have changed the SSH port. To verify this, you can use the below command:

$ netstat -tunl | grep 33000
tcp        0      0 0.0.0.0:33000           0.0.0.0:*               LISTEN     
tcp6       0      0 :::33000                :::*                    LISTEN    

Conclusion

Through this tutorial, we have learned how to change ssh port on centOS 8.

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