Auto SSH Login without Password

The SSH daemon validates SSH client access by Linux system verification via /etc/passwd, or by public/private key cryptography approach.

By using the public/private cryptography approach, we can do a SSH without password.

In my write-up it is for root-to-root connection. You can use it for user connections


Steps 1: At the Host Machine

1. Logon to the root home directory.
2. Make sure the hidden .ssh directory has the permission 700. If not execute the command
   

   chmod 700 .ssh

3. Change Directory to .ssh directory by executing the command
   

   cd .ssh

4. Generate the public-private keys using the ssh-keygen command.
   

   # ssh-keygen -t rsa 

5. The resulting file id_rsa and id_rsa.pub rsa type public key

# ssh-copy-id -i ~/.ssh/id_rsa.pub remote-host

(ssh-copy-id appends the keys to the remote-host’s .ssh/authorized_key)

Step 2: At the Remote Machine, test it out

1. 
   

   # ssh remote-host 
   (It should automatically login)

Reading Articles:

• SSH Auto Login Or Passwordless Login
• SSH Tutorial for LINUX
• 3 Steps to Perform SSH Login Without Password