Hi,
I'm a real newbie in Linux, and I don't even know where and what to search for, in order to do what i have in mind. I would appreciate any help.

Here's what I want to do...

I have a file server on my network, accesed internal by ftp. I have an external IP for this server, but the problem is that all ports are blocked by the ISP (and I can't do nothing about this), except for port 22. I want to let other friends outside my netork acces the server, and the only way would be using a SSH Secure File Transfer Client. Of course, I cannot let them use the root account. I need to create an user (or multiple users on one group) that would have restricted acces to most of the commands (as many as possible, even all), the only thing that i'm interested in is that to let them copy files from several directories (practically I want to simulate a ftp server).

It can be done?
If someone knows what I have to do, or where to search for please let me know.

Thanks a lot.

why don't you just use port 22 for ftp?

Edit: You can use non standard ports for services

From what I know a ftp server requiers two ports (normally 20 and 21) so...

look at scponly:

http://freshmeat.net/projects/scponly/

port 22 is actually a common non-standard port for ftp. Try google for "non-standard ftp ports" and "port 22 ftp"

Are you behind a router?

A friend of mine allready tried using port 22 for a ftp server and it not worked.
I am behind a router, at my ISP, and probably a PIX firewall.

For now I think I can solve it using that scponly shell.

Thanks for helping. I'll be back with more question if that won't work.