IP address (short for Internet Protocol Address) is a unique identifier for any device connected to a network built using the IP protocol.
An IP address is a 32-bit (IPv4) or 128-bit (IPv6) binary number. The common form of writing an IP address is to write the IP address as four decimal numbers (0 – 255) separated by periods, such as 126.96.36.199. Within the same network (Internet, local area network), all addresses must be unique.
An IP address consists of two important parts: a network number and a host number. In the case of a private isolated network, its address can be chosen from the blocks of addresses reserved for such networks, for example, 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8. When the network must operate as part of the Internet, the network address is issued by the provider or by the regional Internet registrar in whose region the network is located (English Regional Internet Registry, RIR) through local Internet registrars (English Local Internet Registries, LIR). There are five RIRs: ARIN, (North America), APNIC (Asia), AfriNIC (Africa), LACNIC (South America) and RIPE NCC (Europe, Central Asia, Middle East).
A static IP address is called if it is specified in the settings of a device connected to the network, or if it is assigned automatically when the device is connected and is used for an unlimited amount of time.
A dynamic IP address is called if it is assigned automatically when connected to a network and is used for a limited period of time, usually until the connection session ends. Also, dynamic addresses are virtual, using NAT technology: users can receive information from the network, but there is no direct access to the device from the network, for example, a computer with a virtual IP address cannot be a WEB server.
Non-virtual IP addresses are called external ("white"). They are mostly static. Quite often, providers position an external IP address as an additional paid service.
To obtain an IP address, the DHCP protocol (Dynamic Host Configuration Protocol) is most often used. This is a protocol that allows devices (hosts) to automatically obtain an IP address and other necessary parameters for networking. The protocol works on a client-server model.
You can easily determine your IP address. For this you need:
- On Windows, you can find out your IP address by running "ipconfig" on the command line.
- On any Unix-like operating system, the IP address can be found by running "ifconfig" on the command line.