The ip property provides the IP address of the client. This tells the server from where on the Internet the request is sent and where to return a response. IP addresses are composed of a set of four numbers. Each is a value between 0 and 255. A sample IP number is 127.0.0.1.Usually the IP address you use when connecting with a host is unique, and no one else on the Net can use that address until you complete your session.
However, there are special cases of caches, proxies, and firewalls that require further study if you plan to use this property.IP addresses can often be used to tell which domain is connecting to the server. By using what is called reverse lookup, the server can often determine the domain name of the client computer. You might use this to determine how many hits are coming from America Online or any other site.