What Is An IP Address?

Date First Published: 27th January 2022

Topic: Computer Networking

Subtopic: Network Identifiers

Article Type: Computer Terms & Definitions

Difficulty Level: 5/10

Learn more about what an IP address is in this article

Short for internet protocol address, an IP address is a string of four unique numbers, separated by full stops that are assigned to a network or a server. IP addresses are provided by ISPs, which uniquely identify every network. IP address space is managed by IANA (Internet Assigned Numbers Authority), which is owned by ICANN.

IP addresses look like this: 127.0.0.1. 127.0.0.1 is the localhost IP address, which refers to the personal computer. IPv4 addresses contain numbers that can range from 0 to 255 and the highest number in the range is 255.255.255.255. The lowest number is 0.0.0.0.

Every device that is connected to the internet has a unique IP address. An IP address contains location information, which can be helpful for delivering content that is relevant to the user's location. For example, some websites use the IP address of the device to automatically set the language, based on the country. IP addresses of servers are usually fixed and rarely change, but IP addresses that are assigned by ISPs can change when the router is turned off and on, or it is possible to ask the ISP to change it.

Note:

The IP addresses of users are not the same everywhere and they do not 'travel with' them. For example, when using public Wi-Fi at a shop or an airport, a different and temporary IP address is assigned by the internet service provider of that shop's or airport's network.

What Makes Up An IP Address?

An IPv4 address is made up of 32 bits, shown as 4 strings of numbers ranging from 0-255. They are shown in decimal form rather than binary form. It is much easier to remember IP addresses that are in decimal form as binary form will be more complex and only consist of 1s and 0s. An IP address in binary form will look like: 10101000.11010100.11100010.11001100. Different classes of IPv4 addresses determine the part that identifies the host or network as well as the range of the first decimal number.

Class A Network

In Class A networks, the first 8 bits of an IPv4 address identify the network and the remaining 24 bits identify the host within the network. For example, in the IP address, 123.123.123.10, '123' identifies the network and '123.123.10' identifies the host within the network. Binary addresses start with 0, meaning that the decimal number can range from 1 to 126.

Class B Network

In Class B networks, the number 127 is reserved for loopback and testing purposes on the local computer (localhost). The first 16 bits of the IPv4 address identify the network and the remaining 16 bits identify the host within the network. For example, in the IP address '132.123.123.10', '132.123' identifies the network and '123.10' identifies the host within the network. Binary addresses start with 10, meaning that the decimal number can range from 128 to 191.

Class C Network

In Class C networks, the first 24 bits of the IPv4 address and the remaining 8 bits identify the host within the network. For example, in the IP address '212.123.123.10', '212.123.123' identifies the network and '10' identifies the host within the network. Binary addresses start with 110, meaning that the decimal number can range from 192 to 223.

Class D Network

In Class D networks, binary addresses start with 1110, meaning that the decimal number can range from 224 to 239. The purpose of Class D was to support multicasting.

Class E Network

In Class E networks, binary addresses start with 1111, meaning that the decimal number can range from 240 to 255. Class E networks are used for the purposes of experimentation and have never been used in a standard way.

Are IP Addresses Publicly Visible?

IP addresses are publicly visible as they can be seen by every server that a network has connected to. Website owners or people that have access to log files that record traffic with the IP address of every visitor can see this information. This can become a slight privacy risk as IP addresses can reveal details about people's network, such as people's town, city, ISP, and sometimes their postcode. It is not possible to find out the exact location of an IP address as only the ISP will know this.

IP addresses could also be used by third parties for tracking the browsing habits of users, such as the pages they visited, what they visited before, the time that they have spent on the website, etc. This can be used to display personalised ads, which some people feel like is a privacy risk. VPNs hide people's real IP addresses by connecting to a server and encrypting traffic, meaning that only the IP address of the VPN can be seen, helping to protect people's online privacy. People concerned about their online privacy often use a VPN.

What Are The Different Types Of IP Addresses?

Two different types of IP addresses include IPv4 and IPv6. IPv4 is the most common type of IP address. It is the fourth version of an IP address that looks like '123.321.123' and it is a 32-bit IP address that is separated by full stops. IPv6 is the sixth version of an IP address. It is the more recent and advanced version and looks like '1234:0fb8:0000:0000:0000:ff00:0012:1234'. IPv6 is a 128-bit alphanumeric address that is separated with colons and contains hexadecimal. The purpose of IPv6 was to resolve issues that are associated with IPv4.

What Is My IP Address?

If you are wondering what your IP address is, your IP address can be found by performing a search with: 'What Is My IP Address' in a search engine, such as Bing or Google. A helpful website for looking up a certain IP address is this website, whatismyipaddress.com. It is also possible to find out your IP address by going into the network settings of your device.

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