SSH Key Login

Note: This article applies to older SSH versions (SSH version 1). For the latest information on SSH key logins, see OpenSSH Public Key Authentication under Ubuntu .

SSH Config for SSH Key customize

On the remote server, the

 / Etc / ssh / sshd_config 

to be edited. Change the following values:

current:

 RSAAuthentification yes

New:

 RSAAuthentification no

current:

 #AuthorizedKeysFile% h / .ssh / authorized_keys

New:

 AuthorizedKeysFile% h / .ssh / authorized_keys

current:

 #IgnoreUserKnowHosts yes
 ChallengeResponseAuthentication yes
 PasswordAuthentification yes

New:

 IgnoreUserKnowHosts yes
 ChallengeResponseAuthentication no
 PasswordAuthentification no
 

Then, restart the SSH service:

 /etc/init.d/ssh restart

Generate a key pair on Linux

ssh-keygen -d

The key pair is now created. Next, you will be prompted for the name of the key and the location.

IMPORTANT: Protect your private key with a password.

You will find it in the home directory of your user

 /home/$USERNAME/.ssh

the key pair.

 id_dsa
 id_dsa.pub

The public key is located in the file

 id_dsa.pub

The contents of this file are now stored on the remote server at:

 /home/$USERNAME/.ssh/authorized_keys

If everything worked out, you should be able to log on to the remote server using the following command:

 ssh $ SERVERIP_ODER_HOSTNAME_DES_ENTFERNTEN_SERVERS -i /home/$USERNAME/.ssh/id_dsa

Root direct login (optional)

DANGER:

Please be careful, otherwise you can lock yourself out. If you forbid the direct root login, there must be another user on the system

SSH is the default tool for Linux administrators. To protect the server better, you should ban the direct root login. You can still log on to the server with another user and then use per

 su

to the root user.

To do this, we edit / etc / ssh / sshd_config and set

 PermitRootLogin yes

on

 PermitRootLogin no