rotocol address) The address of a connected device in a TCP/IP network, which is the worldwide standard both in-house and on the Internet. Every desktop and laptop computer, server, scanner, printer, modem, router, smartphone, tablet and smart TV is assigned an IP address, and every packet (Web, email, video, etc.) traversing an IP network contains a source IP address and a destination IP address.
Public and Private Addresses
For homes and small businesses, the entire local network (LAN) is exposed to the Internet via one public IP address. Large companies may have several public IPs.
In contrast, the devices within the local network use private addresses not reachable from the outside world, and the router enforces this standard. The same private address ranges are used in every network, which means every computer within the company has the identical private IP address of a computer in thousands of other companies. See private IP address
Logical vs. Physical
An IP address is a logical address that is assigned by software residing in the router or server, and that logical address can change from time to time. For example, a laptop is likely to be assigned a new IP when it starts up in a different hotspot (see DHCP
). However, there is a physical address built into every unit of hardware, which cannot change (see MAC address
). In order to locate a device in an IP network, the logical IP address is converted to a physical address by a resolution protocol (see ARP
Static and Dynamic IP
Network infrastructure devices such as servers, routers and firewalls are assigned permanent "static" IP addresses. A user's machine can also be assigned a non-changing static IP by the network administrator; however, it is generally configured to accept an address automatically (see DHCP
). Internet service providers may periodically change the IPs in the modems of their home users, but business users must have consistent "static" IPs for servers that face the public. See dynamic IP address
and static IP address
Version 4 and 6 (IPv4 and IPv6)
The original IP Version 4 addressing scheme defined 32 bits to hold the IP address, and it is still widely used today. However, a larger Version 6 address was subsequently created, and both are in use. It will take a long time before the newer IPv6 is the only system in use. See IPv4 addressing
What's My IP Address?
Various websites report the user's IP address by merely going to the site. IP Chicken is one of them.