IP address ( Transmission Control Protocol/Internet Protocol )

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. The InterNIC Registration Service assigns Internet addresses from the following three classes.

• Class A - supports 16 million hosts on each of 127 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.

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Solutions for IP address shortage - article
Provides details on subnetting, private addressing, classless inter-domain routing (CIDR), and the IP version 6 protocol upgrade. From the March 1997 issue of Data Communications Magazine. Updated on Aug 27, 1997

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. Updated on May 16, 1998

Understanding IP addressing
Excellent overview of IP addressing from 3Com. Also includes a large section on subnetting. Updated on Apr 25, 1998

Changing an IP address in Windows 95
Provides simple instructions for changing an IP address in
Windows 95.

Classes of IP addresses
Describes the classes of IP addresses and contains links to a collection of RFCs relating to IP addresses. Updated on May 5, 1998

Configuring IP
This document, from Cisco Systems, describes how to configure the IP protocol. Updated on Dec 24, 1997

Fast Guide to DNS
Explanation of DNS concepts such as IP addresses, resolvers, domain name servers, redundancy, e-mail routing, and domain name allocation. Updated on Mar 29, 1998

Find out your IP address This site displays your current IP address.

IP address construction This article explains dotted decimal notation and flat and hierarchical networks and includes links to related information.

IP address to longtitude/latitude
Provides a form that converts host names, domain names, or IP addresses to locations with longitude and latitude data. US sites are resolved to the city, Canadian sites to their province, and other non-US sites to the country's capital. Updated on Dec 18, 1997

IP addressing overview
Contains a basic overview of IP addressing. Updated on Apr 29, 1998

IP addressing tutorial
This short tutorial convers the basics of IP addressing and includes a form to enter an IP address and find out its class, network address and node address. Updated on Mar 29, 1998