SSH password-free Login

SSH password-free Login

SSH password-less logon requires the public key and private key. In Linux, ssh-keygen can be used to generate public/private key pairs. The following uses CentOS as an example.

There are machines A (192.168.1.155) and B (192.168.1.181 ). Now I want A to log on to B via ssh without A password.

1. Generate A public/private key pair on host.

[Bkjia @ A ~] $ Ssh-keygen-t rsa-p''

-P indicates the password.-P ''indicates that the password is empty, or you do not need the-P parameter. In this case, you have to press enter three times and press enter once with-P.
It generates the. ssh directory under/home/bkjia, and id_rsa and id_rsa.pub under. ssh.

2. Copy id_rsa.pub under machine A to machine B. In the. ssh/authorized_keys file of machine B, I use scp to copy.

[Bkjia @ A ~] $ Scp. ssh/id_rsa.pub [email protected]:/home/bkjia/id_rsa.pub
[Email protected]'s password:
Id_rsa.pub 100% 223 0.2KB/s

Because no password-free logon is available, you need to enter the password.

3. Machine B adds id_rsa.pub copied from machine A to the. ssh/authorzied_keys file.

[Bkjia @ B ~] $ Cat id_rsa.pub>. ssh/authorized_keys
[Bkjia @ B ~] $ Chmod 600. ssh/authorized_keys

The authorized_keys permission is 600.

4. Machine A logs on to machine B.

[Bkjia @ A ~] $ Ssh 192.168.1.181
The authenticity of host' 192. 168.1.181 (192.168.1.181) 'can't be established.
RSA key fingerprint is 00: a6: a8: 87: eb: c7: 40: 10: 39: cc: a0: eb: 50: d9: 6a: 5b.
Are you sure you want to continue connecting (yes/no )? Yes
Warning: Permanently added '192. 168.1.181 '(RSA) to the list of known hosts.
Last login: Thu Jul 3 09:53:18 2008 from bkjia
[Chenlb @ B ~] $

When logging on for the first time, you must enter yes.

Now machine A can log on to machine B without A password.

Summary: The logon host has a private key, and the logged-on host must have a public key. This public/private key pair is generally generated on the host machine of the private key. The above is a public/private key pair using the rsa algorithm. Of course, you can also use dsa (the corresponding file is id_dsa, id_dsa.pub)

If you want A and B to log on to each other without A password, configure the same method as above.

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