How to Install SSH server and use it on Debian

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General
You wish to install an SSH server on your computer and you do not know how? You are in the right place because every thing is explained below. From how to install SSH to configuring SSH server to use it in GNU/Linux Debian operating system.


SSH History
SSH to connect remotely to a computer. There are two known protocols to connect remote:

Telnet : Telnet is the most basic protocol to connect remotely to a computer. It is hardly used because it does not encrypt (protect) no data, so if a hacker "listening" to your connection to the server, it will have the password for the server, for example. Telnet used extensively to test services (HTTP, POP, SMTP, etc..) And whether they work.

SSH : SSH is the protocol most used, because it encrypts the data, and a hacker can not listen to your connection. The first version of SSH was released in 1995. This version was a failure because it does not check if the data received were appropriate ones and that made it vulnerable to active attacks. SSH Version 2 was developed by the research team of the IETF. This version was released in 2006.

SSH is recommended because it encrypts the data and this makes it difficult for hackers.

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Installing SSH
To install SSH, nothing is easier than this. Just issue the following command in the terminal as a root user.
The command is:
Code:

sudo apt-get install ssh

Note: If you are already logged into superuser (root), you should not do sudo.

That's it. You have installed SSH. In the next section, we will connect to SSH and after secure. Remember that if you have a router, you must open port 22 if you want to connect remotely.


Configuring SSH
To configure SSH, we will use nano to edit the configuration file.
To edit the file, type this command in the terminal as a root user
Code:

sudo nano / etc / ssh / sshd_config

Here, we use the nano text editor (nothing prevents you from using another editor text.)

Here are some interesting sections of the configuration you can change:

Code:

# What ports, IPs and protocols we listen for Port 22

This section allows you to configure the listening port of the server. For a security issue, you can change this option because it will hurt a bit to hackers.

Code:

# Use options to restrict contention Which interfaces / protocols sshd bind to # Will ListenAddress:: # ListenAddress 0.0.0.0

This section allows to tell the server to listen only on certain IP addresses. To do this, remove the # and the second ListenAdress replace 0.0.0.0 with your IP address.

Code:

# Authentication: yes PermitRootLogin LoginGraceTime 120

This section allows you to configure authentication. Option LoginGraceTime is the maximum waiting time after connecting to SSH for identification. The time in seconds.

PermitRootLogin can say whether or not authorized SSH connection to the root account. For safety, it is recommended that you set this option to No. This is important options for this server. You can change all other options to your liking if you want.

To restart the server, just issue the following in the terminal as a root user
Code:

sudo / etc / init.d / ssh restart

Explanation
Code:

/ etc / init.d / ssh

This is the program that lets you start, stop or restart SSH.
Code:

restart

This tells the program to restart SSH.

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SSH Connection for Linux
To connect to your SSH server from Linux, use the following command
Code:

ssh the_address

Explanation:
Code:

ssh

Is the program name of the SSH service
Code:

the_address

Replace this with the address of your server.

At your first login you will have a warning stating that the server is not recognized. Just type in yes and press Enter after.
Code:

test @: / etc / ssh $ ssh localhost The authenticity of host 'localhost (127.0.0.1)' 
can not be established. Are you sure to continue Connecting you want (yes / no)? yes

After it asks for a password. By default, it takes as the user account you are currently using (in my case: test). You may be forced to use another user by adding the -l option before you connect:
Code:

ssh -l user testname

When your server connection is established, this text appears:
Code:

testusr @ testname password:

Server asks for your password, then type it. It's normal that it would not appear because it is a security. After entering your password, you are finally connected to your computer. You should see something like this:
Code:

test @: / etc / ssh $ ssh localhost test @ localhost's password: Linux 2.6.22 lebelw-14-generic

You will see more information on your terminal than this. If you see this, then you're connected to your computer successfully.

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SSH Connection for Windows
To connect via SSH from Windows, you can use the software Putty. You can download it from their official site. Once it is downloaded, open. You should see this:

To connect to your server, simply type the server address in Host Name (or IP address) and click Open .

A warning will appear:

Just click Yes.

Then you will see a console like this:


Just type your user name.
Then type your password. It appears that nothing is normal, it is a security.

If all goes well, you'll see an image similar to this:

Now you know how to install an SSH server and how you connect from Windows and Linux.

OpenSSH:
OpenSSH is a free version of the protocol suite of SSH , tools for network connectivity on which a growing number of people are seated on the Internet. Many users of telnet, Rlogin, FTP , or other programs are identical, do not realize that their password is transmitted across networks in cleartext. OpenSSH encrypts all traffic (including passwords). OpenSSH also provides a variety of authentication methods. As its name suggests, OpenSSH is developed under the project.