How Do I Get IP Address of Referrer?

Is there a way to check for the IP address of referrer? I want to know the IP address of where the SWF is being hosted at.

The reason why I ask is that we host multiple sites from the same ip address with elaborate url masking. Rather than always adding/changing the server side code to allow for all these different sites, or changing the relevent .xml config file, I think it'd be easier to just check for the IP address of where the SWF is being hosted in.

Unfortunately, Client.ip only gives you the page that uses the SWF, not where the SWF is actually being hosted in.

Any idea on how to get this? Many thanks!!!