SSH password-free login configuration operation

I) generate public and private keys locally

1) [root@SamuluIndex ~] # cd .ssh

2) [root@SamuluIndex .ssh] # rm-f * (clear all old files in the .ssh directory)

3) [root@SamuluIndex .ssh] # ssh-keygen. Press enter in three places that need to be entered in the process.

Id_rsa and id_rsa.pub are generated in the .ssh directory. Where id_rsa is the private key, which is used by the local machine, and id_rsa.pub is the public key, which is used by other machines.

(2) upload the public key to the remote host

[root@SamuluIndex .ssh] # scp id_rsa.pub root@172.20.0.141:/root/.ssh

After you are prompted to enter the password for the remote host (172.20.0.141), you can see the prompt for a successful upload:

Id_rsa.pub 100% 398 0.4KB/s 00:00

(3) Log in to the remote host and write the client public key to the authorized_keys file

[root@SamuluIndex .ssh] # ssh 172.20.0.141

Warning: Permanently added '172.20.0.141' (RSA) to the list of known hosts.

Root@172.20.0.141's password:

Last login: Tue Apr 29 21:09:27 2014 from 192.168.0.56

[root@tixa ~] # cd .ssh

[root@tixa .ssh] # cat id_rsa.pub > > authorized_keys

At this point, you can see two files, authorized_keys and id_rsa.pub, in the .ssh directory of the 141machine. The main purpose of id_rsa.pub is to write public key information into authorized_keys. Then delete the id_rsa.pub from both hosts, otherwise the machine will not be able to log in to other machines without a password.

(4) exit the remote host and log in to the remote host again

At this point, it is found that you can log in to remote machine 141 without a password on 100 machines.

And two files are kept in .ssh on the100th machine: id_rsa and known_hosts, and one file in .ssh on the141machine: authorized_keys.