isr.co.ro : glossary IP Address The unique 32-bit number assigned to each host computer on the Internet, or a similar number for each machine on a similarly-designed internal "intranet." Interpreted correctly, the bits specify the class of network and its number, as well as the subnetwork that specifies a particular machine or group of machines. When you send a message using a Domain Name System (DNS) address, the DNS servers on your system translate it to an IP address for actual message routing and delivery. To make it easier for humans to work with IP numbers, they're generally written in "dotted decimal notation" showing four decimal numbers between 0 and 255 separated by periods, such as "127.1.2.3".