What is an IP address?
An IP address is a 32-bit number that identifies a host on a network. It is usually written in the form of the four decimal numbers seperated by periods (e.g. 10.50.201.1).
In contrast to MAC addresses, which are physical addresses, IP addresses are logical addresses. A devices that wants to communicate with other devices on the network using TCP/IP needs to have an IP address configured. The IP address can be configured manually or it can be obtained from a DHCP server.
The term IP address usually refers to IPv4, the fourth version of the IP protocol. A newer version exists (IPv6) and uses 128-bit addressing.
Private IP addresses
There are three ranges of addresses that can be used in private networks (e.g. your home or office LAN). These addresses are not routable on the Internet.
Private addresses ranges are:
- 10.0.0.0 – 10.255.255.255
- 172.16.0.0 – 172.31.255.255
- 192.168.0.0 – 192.168.255.255
Public IP addresses
Public IP addresses are assigned to computers that connect to the Internet. It is an address that your computer (or your router) gets from your ISP when you connect to the Internet. To find out your public IP address, you can use this tool.