CentOS Linux

It is quite important to know some of the configuration settings possible with the open SSH server applications and how to change them on your Ubuntu system. Open SSH is freely available. It is a type of the Secure Shell (SSH) family of tools for controlling files remotely or for transferring files between two computers. SSH replaced Telnet because it was not secure.

Open SSH provides a server da emon and tools to facilitate secure and control file transfer operations. Installation is simple.

Installing SSH On Ubuntu

  1. Press ctrl-Alt-T on the keyboard to open terminal.When terminal opens, run the necessary commands to install the SSH server.

enable ssh2. Use your SSH clients to connect to your machine using the default port 22.If you wish to change the connection port, run the commands below to open the configuration file: ‘sudo gedit/etc/ssh/ssht_config’

enable ssh 23. Change the port number to whatever you want and then save the file.Use this number every time you want to connect to your system through SSH.

enable ssh 3

The open SSH-server package can also be selected to install during the Server Edition installation process.

SSH Keys

The SSH keys allow transfer of files between two computers without asking for  a password.SSH key uses two keys, a public key and a private key. To develop the keys from a terminal you enter the necessary commands.

This will develop keys using RSA Algorithm. The keys are saved in specific files. Finally you double check the permissions on the authorized key files, only the validated user should have the permissions to read and write. You can SSH to the host computer without being asked for a password.


You can configure the default behavior of the SSH server application by editing the configuration file. If you want information about the configuration directives which have been used in the configuration file, you can check the necessary manual page which you get from entering the appropriate commands. Such things like communication settings and authentication modes are controlled by SSH directives in the configuration files. You can edit the configuration file but you have to make a copy of original file.

Enabling SSH is as easy as that. You have no reason to wait until a computer technician does it for you. Follow the steps above and within a few minutes you will achieve desired results.

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