Introduction to SSH
Security is a paramount concern when it comes to communication over the internet. One of the protocols used for secure remote access is SSH.
SSH, which stands for Secure Shell, is a network protocol that ensures encrypted communication between client and server, preventing unauthorized access and eavesdropping.
Command to Access Server
To access a server using SSH, you need the SSH command. The typical format of the command is “ssh username@IP address.” The username is the user’s name on the server, and the IP address is the server’s address.
SSH default port for communication is Port 22.
SSH Default Port
SSH uses a default communication port of 22, which is known to most attackers. However, using this port presents a security risk since it is vulnerable to brute-force attacks, where an automated tool uses a trial and error method to guess login credentials.
Changing the Default SSH Port
To change the default SSH port, you can choose a new port to use for communication. However, you should note that the chosen port must be within the Dynamic/Private Port range.
Ports within this range are reserved for private use and are less prone to attacks. The steps to change your default SSH port include:
1.
Select a new port: You can use any number within the range of 1024 to 65535, except those already reserved for other purposes. 2.
Edit the sshd_config file: To edit the sshd_config file, enter the following command:
sudo nano /etc/ssh/sshd_config
This command opens the sshd_config file in a text editor. 3.
Locate the line that states “Port 22” and change it to reflect the new port number. For instance, if you choose to use port number 5151, replace the text “Port 22” with “Port 5151.”
4.
Save the changes and exit the editor. 5.
Restart the SSH service: To apply the changes, you need to restart the SSH service. Use the following command:
sudo service ssh restart
6.
Test the changes: After restarting the SSH service, test whether the new port is working correctly using the following command:
ssh username@IP address -p (new port number)
Conclusion
In conclusion, using SSH for remote access to servers is vital for security; however, you need to take additional measures to prevent brute force attacks. Changing the default communication port from port 22 to a new port is one of the steps you can take to enhance security.
The process of changing the port number involves selecting a new port, editing the sshd_config file, restarting the SSH service, and testing the changes. By following these steps, you can add an extra layer of security to your server’s communication.
In summary, SSH is a network protocol that enables secure communication between client and server, preventing unauthorized access and eavesdropping. It uses a default communication port of 22, which is vulnerable to brute force attacks.
Changing the default port to a new one within the Dynamic/Private Port range is one of the steps you can take to enhance security. The process involves selecting a new port, editing the sshd_config file, restarting the SSH service, and testing the changes.
By taking these extra measures, you can add an extra layer of security to your server’s communication. In today’s world, where security is a paramount concern, it is crucial to use secure protocols like SSH to protect your data from prying eyes.