nx and ssh restrictions?

[Trond Mæhlum <trond@maehlum.net>]

We would like to set up nx login for our teachers. This seems like the 
best way to provide access from home. We are experimenting with 
nxbuilder, which seem to work great.

But when ssh is set up, it is also possible to do ssh straight into the 
server as a user. We do not want this.

I thought that an nx login was performed as the user 'nx' with a key. 
Then the user logs onto the server through the tunnel set up by nx. This 
doesn't seem to be right. When I try to edit the ssh config to allow 
only nx, an nx login as user does not work anymore.

Have I misunderstood how nx logins work? Can someone please advice me on 
how to set this up?

I do want nx logins, but no ssh logins with user/password.

--
Regards
Trond Mæhlum