查看“Limit the user accounts that can connect through OpenSSH remotely”的源代码

==== How to limit the user accounts that can connect through ssh remotely ====
*Note: When you initially enable the SSH server, any user with a valid account can connect remotely. This can lead to security risks because password cracking tools exist that try common username/password pairs. This method helps restrict login access.

*Keep a backup of the ssh server configuration file:
   
 sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.ORIGINAL

*Edit the configuration file:
 gksudo gedit /etc/ssh/sshd_config

*Change the parameter:
 PermitRootLogin no

This disallows the root user from connecting through SSH remotely.

*Add the parameter:

 AllowUsers <user1> <user2> ...

and specify the usernames (space separated) that can connect remotely.

NOTE: This will allow ONLY the users specified to connect. You may use wildcards here (example: j* will allow jsmith to connect but not fsmith).

*You can also use:

 DenyUsers <user1> <User2> ...

and specify, again using wildcards, users restricted from using SSH.

*If you enable the OpenSSH server and you do not wish to enable <i>any</i> remote connections, you may add:
 AllowUsers nosuchuserhere