Key Based / Passwordless SSH Authentication on Linux Servers

Overview :

Password Less authentication to Linux servers makes the system admin’s life easy. To Implement password less or Keys based authentication we have to generate Public and Private keys , Copy the Pubic keys to remote Linux servers either manually or by ssh-copy-id command .

In My scenario I have Ubuntu laptop and daily I have to login to lot of remote Linux servers , Follow the below steps to achieve password less / Keys based authentication :

 

Step:1 Generate Public and Private keys , using below command

# ssh-keygen -t rsa

ssh-keygen

Above command will save the keys under ~/.ssh  directory with the name id_rsa & id_rsa.pub. Leave the passpharse empty while executing above command.

Step:2 Copy the public key to remote linux servers

# ssh-copy-id   -i   /root/.ssh/id_rsa.pub root@mail1.nsitmail.com

ssh-copyid

ssh-copy-id command will automatically copy the contents of id_rsa.pub file to ~/.ssh/authorized_keys file of remote linux server

Note :  if we don’t want to use ssh-copy-id command , then manually Append contents of  file “id_rsa.pub” to  “~/.ssh/authorized_keys” remote linux server  and  change the permissions of “~/.ssh/authorized_keys” to  755.

Example:3  Now access the remote linux server and it will not ask for the password.

passwordless-ssh


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