- A Programmer's Life

Setup SSH Passwordless Login In Linux

For login to remote server without password you need to generate the ssh key.

This is a note for myself, hope that would be helpful for someone else.

Summary:

You want to connect from your local ( Local  ) to your cloud ( Cloud )

Below are steps to setup login for SSH without enter password:


1 - Generate SSH Private/Public key:

Use the below command to generate the RSA ssh key on your local

# ssh-keygen -t rsa


2 - View generated SSH Private/Public key:

The private/public key has been generated and stored at “/root/.ssh/”. Go to the corresponding directory and see the generated keys. See the output.

# cd /root/.ssh/
[root@2daygeek .ssh]# ll -h
total 12K
-rw------- 1 root root 1.7K Dec 18 13:01 id_rsa
-rw-r--r-- 1 root root 419 Dec 18 13:01 id_rsa.pub
-rw-r--r-- 1 root root 1.6K Aug 23 08:15 known_hosts


3 - The id_rsa.pub key is below:

Use the below command to view the id_rsa.pub details

# cat id_rsa.pub
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA0JOae6XhB1NccSrms4NpuLufOiMu10ObKoxWHtQ5oVXUvCuFz7Vxp5eKIGmizLtZoFxi3DOKcuV
tP9FA5YMpqa6umEKAtJSIVgwZGBWvpkGElqvpP5r720f3XScpHkL/t/AnCPVeDn2jtL4XBkMDacOViD8m9P/TtQXthDqR3ZTtixsAXACm/bjLJKtUJUqrzTbM5LfQe7hh1xq8EyCXF6shvuXS/
0GUvyjPhGPkhFGIjFrPwbWnw8qudzBIlbGEMhboVwDeqJohDd7nkd2Ww0VyBMplJwEs2VGdI/HNwHKXp2HNgbJBCkWvNe7Aq3YekV/aqgd7QPjasZf8OM1hAVjWoVw== root@local.chilieu.me


4 -  Copy the public key to Cloud using ssh-copy-id:

# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.123

The authenticity of host '

192.168.1.123

(192.168.1.123)' can't be established.
RSA key fingerprint is 6f:ad:07:15:65:bf:54:a6:8c:5f:c4:3b:99:e5:2d:34.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.123' (RSA) to the list of known hosts.
root@192.168.1.123's password:
Now try logging into the machine, with "ssh 'root@192.168.1.123'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

Note :

The ssh-copy-id copy the id_rsa.pub key to remote server with name of authorized_key under “/root/.ssh/”.

5 -  Try access Cloud server without Password 

Now, you can access the remote host without entering password. like below

# ssh root@192.168.1.123
Last login: Wed Dec 18 13:00:57 2013 from 219.91.219.14
[root@s15405085 ~]#


Hope you find it helpful, if you have any question, comment below

Happy Coding!