SSH passwordless

Berikut adalah trik passwordless di linux

root@mail:~# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
7a:b0:b6:ff:52:97:9d:d0:9a:a4:d9:2a:6c:03:6a:c9 root@mail
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|                 |
|             .   |
|            o .  |
|      . S  = * . |
|      .+  + * o  |
|   . o+o.. o     |
|    E. o* .      |
|   .  .o.=.      |
+-----------------+
root@mail:~# ssh-copy-id -i /root/.ssh/id_rsa.pub
ssh: Could not resolve hostname /root/.ssh/id_rsa.pub: Name or service not known
root@mail:~# ssh-copy-id -i /root/.ssh/id_rsa.pub root@proton
root@proton's password:
Now try logging into the machine, with "ssh 'root@proton'", and check in:
  .ssh/authorized_keys
to make sure we haven't added extra keys that you weren't expecting.
root@mail:~# ssh root@proton
Last login: Fri Dec 14 12:48:55 2012 from mail.ns.maspion.net
[root@proton ~]# exit
logout
Connection to proton closed.
root@mail:~#