February 7, 2016 at 10:39 #1191Michael DunnParticipant
Hi guys, I have a little question. I am an amateur CentOS Linux user and recently upgraded from CentOS 5.5 to CentOS 6. How do I change default sshd tcp port CentOS Linux version 5/6? Basically, how to change the SSH port?
February 7, 2016 at 12:12 #1192wangariParticipant
How to change SSH Port
The variety of ways to secure your server is innumerable. There are however some elementary steps and procedures that you can implement to cover your bases.
When using a Linux server it is possible to change the SSH port from the default port (22).
The following steps help you to do just that.
Step 1. Reconfigure SSHD
One of the simplest ways of changing the port is to SSH into the server as root.
NB: Replace hostname/IP with your server’s hostname or the main IP address of the same.
So now that you are logged into the server as root, let’s begin editing the sshd_config file.
Disclaimer: It is continually a great idea to backup any server file that you intend to make changes on.
cp /etc/ssh/sshd_config /etc/ssh/sshd_config_backup
Now we can modify the file.
Using your preferred text editor, open /etc/ssh/sshd_config and identify the line that specifies the port. Unless your sshd_config file has been altered, the default setting is commented out with a #symbol as shown in the following example
# symbol informs the server to ignore everything that comes after it on the same line.
That character will need to be removed and the number 22 changed to something else.
NB: Ensure the port number you pick is not in use elsewhere. There is a list by Wikipedia of port numbers and their uses. You can use this to refer and pick a port number that is not in use or listed. For purposes of this examples we will apply port 2222 (a windows server port but not a default on Linux servers).
Proceed to remove the # and change port number
Save changes and close the sshd_config file.
The new port also needs to be opened in the server’s firewall. This procedure explains firewall changes on a solitary VPS or dedicated server. In the instance of a hardware firewall in place, contact support for the necessary changes to be made.
Step 2: Updating Firewall
Here is a post on how to update the firewall.
Step 3: Restart services
APF and SSH must be restarted now to activate the changes made. Run the command ‘/etc/init.d/apf restart’ then ‘/etc/init.d/sshd restart
service sshd restart
service apf restart
SSH will have restarted and listening on the specified port number.
Note: Changing the SSH’s port number alters the way you run some commands that utilize SSH and need the new port number include scp and rsync.
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