The server variables where blank and so was the User.Identity.Name

I also tried...

System.Security.Principal.WindowsIdentity.GetCurrent().Name
System.Threading.Thread.CurrentPrincipal.Identity.Name

again no luck.

Obviously this is to be expected due to it being set to Anonymous!

Thanks for you help Mendhak, i'll look at using the X-FORWARDED-FOR with getting the correct IP address.

Would you know of a command (ASP or DOS) which i can use that will use the IP address to return back the login name?