how to restrict a web portal to a particular computer?

I am in the process of creating a Ruby on rails portal

This portal requires a lot of data feeding by the site owner's back-office personnel.

My client has this problem :

the office staff should not be able to access the back office interface from any other than his office compu开发者_如何学Goters

I have no idea how to achieve this. Is there a method for this?

Thanks in advance.

Edit:

Is tracking the Mac address a good solution.? is it possible if a ok?

I don't think that you should do anything in rails - this should be configured elsewhere. If rails is running on Apache then see mod_access.

The best way to set this up is to have the app hosted INSIDE the organisation's firewall. Best option - server lives inside the company on a subnet isolated entirely from direct internet access.

If you currently host outside the company, you can set up a firewall that prevents access from unknown IP addresses. You would only accept requests that come from the company's IP ranges. Ideally, you do this at the host/operating system level.

If that can't work, you can do add to your Rails authentication - detect the IP address of the request and if it is not in the company range, prevent access.

found a solution. Using a java applet one can access the machine's hardware details including MAC address. am using this idea.