centos password-free login

Preparations:
    1. Confirm the local sshd configuration file (requires root permissions)
　　$ gedit /etc/ssh/sshd_config
　　Find the following, and remove the comment "#"
　　RSAAuthentication yes
　　PubkeyAuthentication yes
　　AuthorizedKeysFile .ssh/authorized_keys
　  2. If modified The configuration file needs to restart the sshd service (requires root permissions)
　　$ /sbin/service sshd restart


Configuring SSH passwordless login requires 3 steps:
    1. Generate public key and private key
    2. Import the public key into the authentication file, change permissions
    3. Test


1 .Generate public key and private key
  Shell code: ssh-keygen -t rsa    generates two files in the ~/.ssh directory by default:     id_rsa : private key     id_rsa.pub : public key 2. Import the public key into the authentication file, change permissions     2.1 Import the native         shell code: cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys       2.2 Import the server for password-free login         First copy the public key to the server
  












        Shell code: scp ~/.ssh/id_rsa.pub xxx@host:/home/id_rsa.pub  


        Then, import the public key into the authentication file (this step is done on the server)
        Shell code: cat /home/id_rsa. pub >> ~/.ssh/authorized_keys      2.3 Change permissions on the server        Shell code: chmod 700 ~/.ssh                     chmod 600 ~/.ssh/authorized_keys