Each device (Computers, iPhone, Tablet PC, iPad) which is connected to a public internet is assigned with a unique numerical digits, these are known as Internet Protocol (IP) address . The IP address of four numbers separated by decimal points (also called 'point four'), looks something like 127.0.0.1. Because these numbers are usually within a specified area block-based Internet service provider, an IP address is often used to determine which country or region from a computer connected to the Internet. Sometimes an IP address can be used to display the user's approximate location. The numbers may be tedious to deal with a IP address may also be assigned to a host name, and sometimes easier to remember. Host name may be payable, that IP address, and vice versa. Internet service providers at the same time send a IP address of each user. These are called static IP addresses. Because there is a limited number of IP addresses, and use the Internet more and more Internet service providers are now in a dynamic IP address the problem the way IP address (using DHCP) pool. These are called dynamic IP address. This also limits the user to host websites, mail servers, FTP servers, in addition to the user to connect to the Internet, and virtual host, a machine can do more than one computer (with multiple domain names and IP addresses).