// In your js file (e.g. app.js)
 var get_ip = require('ipware')().get_ip;
 app.use(function(req, res, next) {
     get_ip(req)
     next();
 });

 // `get_ip` adds two fields to your request object
 // 1. `clientIP`, 2. `clientIpRoutable`
 // Where:
 //    `clientIP` holds the client's IP address
 //    'clientIpRoutable` is `true` if user's IP is `public`. (externally route-able)
 //                       is `false` if user's IP is `private`. (not externally route-able)

 // You can also use your own config file as below.
 // for `IPWARE_HTTP_HEADER_PRECEDENCE_ORDER` items, the
 // check is done from top to bottom where the request `headers`
 // is examined for the existence of the IP address field.

 // All lists that start with `IPV` are examined and if an IP
 // address starts with any of those patterns the IP is considered
 // `private`, otherwise the IP is considered `public` which means
 // the IP is externally routable. (reachable through the Internet :)

 // Simply copy the following content into a JSON file and
 // modify it to suit your needs and place it in your project
 // under version control.

 // Then you can use it like:
 // var get_ip = require('ipware')('../path/to/your/conf.json').get_ip;

 {
   "IPWARE_HTTP_HEADER_PRECEDENCE_ORDER": [
     "HTTP_X_FORWARDED_FOR",
     "HTTP_CLIENT_IP",
     "HTTP_X_REAL_IP",
     "HTTP_X_FORWARDED",
     "HTTP_X_CLUSTER_CLIENT_IP",
     "HTTP_FORWARDED_FOR",
     "HTTP_FORWARDED",
     "HTTP_VIA",
     "REMOTE_ADDR"
   ],

   "IPV4_EXTERNALLY_NON_ROUTABLE_IP_PREFIX": [
     "0.",
     "1.",
     "2."
   ],

   "IPV4_CLASS_A_PRIVATE_BLOCK_IP_PREFIX": [
     "10."
   ],

   "IPV4_LOCAL_LINK_BLOCK_IP_PREFIX": [
     "169.254."
   ],

   "IPV4_CLASS_B_PRIVATE_BLOCK_IP_PREFIX": [
     "172.16.",
     "172.17.",
     "172.18.",
     "172.19.",
     "172.20.",
     "172.21.",
     "172.22.",
     "172.23.",
     "172.24.",
     "172.25.",
     "172.26.",
     "172.27.",
     "172.28.",
     "172.29.",
     "172.30.",
     "172.31."
   ],

   "IPV4_EXAMPLE_CODE_DOCUMENTATION_IP_PREFIX": [
     "192.0.2."
   ],

   "IPV4_CLASS_C_PRIVATE_BLOCK_IP_PREFIX": [
     "192.168."
   ],

   "IPV4_RODCAST_IP_PREFIX": [
     "255.255.255."
   ],

   "IPV4_LOOPBACK_IP_PREFIX": [
     "127."
   ],

   "IPV6_EXAMPLE_CODE_DOCUMENTATION_IP_PREFIX": [
     "2001:db8:"
   ],

   "IPV6_CLASS_PRIVATE_BLOCK_IP_PREFIX": [
     "fc00:"
   ],

   "IPV6_LOCAL_LINK_UNICAST_IP_PREFIX": [
     "fe80:"
   ],

   "IPV6_MULTICAST_IP_PREFIX": [
     "ff00:"
   ],

   "IPV6_LOOPBACK_IP_PREFIX": [
     "::1"
   ]
 }