Editing How to do a SSH authentication without password

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'''Introduction''' 

Each time you want to connect to an external server you need your password... You're tired? I propose a method to avoid having to enter password. 

To do this we will use the '''SSH key''' with DSA encryption ( it exist also and RSA encryption, the choice is completely arbitrary)

Principle is simple: 
*You create an encrypted SSH key for your user (user_local) on the local computer (local)
*You send a public part of it to your user (user_server) on the distant server (for example kimik2)


'''Create a SSH encrypted key on the local machine'''

The key is composed of two file: id_dsa and id_dsa.pub.
*id_dsa is the '''private''' key!!! '''DO NOT DIVULGE !!!'''
*id_dsa.pub is the public key.

First, check if you have or not this key. It is located in the .ssh directory

      /home/user_local/.ssh/

If there is already this two file, go to the last part of this tutorial, else let's create this files. It is very easy via the keygen function:

       ssh-keygen -t dsa

The computer ask you: 
       Enter file in which to save the key (/home/user_local/.ssh/id_dsa): 
       Enter passphrase (empty for no passphrase):
I let the first empty to have the default name. Then the computer ask you for a '''passphrase'''. Of course '''you have to put one''' for your security (I don't put passphrase). This passphrase will be ask at each new local session.

If everything is OK, the 'echo' is:
      Your identification has been saved in /home/user_local/.ssh/id_dsa.
      Your public key has been saved in /home/user_local/.ssh/id_dsa.pub.
      The key fingerprint is:
      7b:53:c3:.................:e8:6c:bb user@local
      The key's randomart image is:
      +--[ DSA 1024]----+
      |                 |
      |                 |
      |                 |
      |           .  .  |
      |        S   ++.o |
      |         . +o+++ |
      |        . +oo +=.|
      |           .E+...|
      +-----------------+

Bravo, you create an SSH encrypted key.


'''Installing SSH public key on the server'''

There are 2 methods. The first is automatic and easy (but not present in all the distributions), the second is manual and easy too. As I'm lazy, I will describe only the automatic. If that doesn't work, go on the web.

*Automated method:

In your openssh utilities, we are using the ''ssh-copy-id''. This command will automatically add your public key (''id_dsa.pub'') of the local computer in the file ''~/.ssh/authorized_keys'' on the distant server. In your local computer, type the command:

      ssh-copy-id user_server@server

After entering your password and your passphrase for the last time, the public key is copied to the user account "user_server" server.


'''''try and feel free to modify this tutorial'''''

In my case, dsa type (ssh-keygen -t dsa) does not work, rsa (default type) works. So maybe try following commands if you meet problems.
    ssh-keygen

    ssh-copy-id -i user_server@server

    ssh user_server@server

http://www.openssh.com/ [[Image:Logo_openssh.png]]

http://en.wikipedia.org/wiki/Ssh-keygen

http://linux.die.net/man/1/ssh-copy-id