IP address Last modified: Friday, September 18, 2009
An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP address. Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to the Internet requires using registered IP addresses (called Internet addresses) to avoid duplicates. The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. Four regional Internet registries -- ARIN, RIPE NCC, LACNIC and APNIC -- assign Internet addresses from the following three classes. Class A - supports 16 million hosts on each of 126 networks Class B - supports 65,000 hosts on each of 16,000 networks Class C - supports 254 hosts on each of 2 million networks The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied to adoption of IPv6. Also see Understanding IP Addressing in the Did You Know . . .? section of Webopedia.
•E-mail this definition to a colleague• For internet.com pages about IP address . Also check out the following links! TCP/IP and IPX routing tutorial  This tutorial supplies information on setting up a relatively simple WAN-connected internetwork or Internet-connected LAN. Includes explanations of IP addresses, classes, netmasks, subnetting, routing, several example networks, and a basic explanation of IPX routing Webopedia's "Did You Know...?" Section  Use this Webopedia knowledge section for an in-depth overview of specific technologies and occurrences in the areas of Computer Science, The Internet, and Computer Hardware and Software. Webopedia's Quick Reference Section  Use this Webopedia reference section for information on common Internet and computer facts and occurrences. Webopedia's Tech Support Area  Read the descriptions of each tech support Web site below, and choose the one that best suits your needs. We offer these links to help users get the tech support they need. LearnToSubnet.Com An educational course on addressing TCP/IP Networks that includes IP Addresses and Subnetting. Topics include: Binary Math, IP Addressing (IP Address), Subnet Mask, and Custom Subnet Mask.	Addressing Internet Routing APIPA APNIC ARIN ARP ccTLD CIDR Class C network DDR DNS domain name dynamic DNS failover FQDN hot potato routing IANA Internet InterNIC IP spoofing martian address Mobile IP NAT ping port scanning RIPE NCC root server system Give Us Your Feedback Shopping IP address Products Compare Products,Prices and Stores Shop by Category: Routers 198 Model Matches Firewalls 93 Model Matches