Hello, I'm new in the forum and which to ask some question.

I'm using Putty to connect to my server.

My question is
How can I eliminate user so that he can only login to the server using SSH?
After the user login, he cannot perform any command(eg: top, free, cd , ls, users and others).

Thank for the helping ^^

If you want to restrict the environment for that user, the easiest way is to use a chroot jail.

http://www.google.com/search?ie=UTF-...sh+chroot+jail

Seems should be easy enough to create a group and specify what that user of that group can/can't do.

Use NetInfo Manager to add a user. Copy an existing GUI account, and change the values associated with it.

If the given user is not supposed to use the cd and ls programs, then he/she will be limited to a single directory without the ability to see what files are available. So the question actually is - what is the user suppossed to do with such a login? If it's only about launching some script once in a while or reading a specific file, then your better off providing a web interface with a PHP or Perl script to launch a task or view a file. Then you don't have to deal with all the hassles of chroot jails and permissions.

The user is only given permission to access the server using SSH but not FTP and other method else.
I ned the user to login and make use the server serve as a proxy server.
So I must disallow user to perform cd/ls command due to the security issue ^^

In other words your setting up an account for the purposes of using a socket 4 proxy over an SSH tunnel I am guessing? presumably with the task of bypassing some firewall in some location?

If you set the user's path up so they see no locations for binary files, that will "cut out" alot of programs, including top, free and users. However their are still ways they can get around it and built in functions of the shell like ls and cd will still work but a chroot root takes care of the problem of them being able to see other users data. Their ability to redefine $PATH is the only thing I can't think of how to block since if they know how to do that they can redefine it to get back access to applications... however despite all of this, the SSH server also included SFTP, if you removed their ability to write to the directory (ie only allow them read permissions) then their abilities with SFTP should be made useless.

Note: You must use the absolute path to the shell, otherwise Terminal will say that an admin has set your shell to an invalid path, and then quit.

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man rbash

you should be able to set up a ssh/user on your proxy, change that users shell to rbash in /etc/passwd.

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