This module reports the IP the user came from, as a JSONP response.
   GET requests required; CGI style arguments are permitted.

     callback=[name]     to call a function name of your choosing
     size=[number]       to bad the http data portion of the response.  (Does not attempt to offset header response)
     asn=1               to do ASN lookups 
     testip=IPADDRESS    to test a specific IP address

   If the callback is "?", it will output to the screen (calling it "callback").
   Any other, and a JSON mime type is used instead.

Example:

   http://test-ipv6.com/ip/?callback=hello&testip=2001:470:1:18::2&asn=1


Returns:
   hello({"ip":"2001:470:1:18::2","type":"ipv6","subtype":"","via":"","asn":"6939","asn_name":"HURRICANE - Hurricane Electric, Inc.","asnlist":"6939","padding":""})

To install:

   ./configure
   make
   sudo make install   
   cat README.configuration