IP address stands for 'Internet Protocol address' and can be used to identify computers and other devices and connect them to a network. It is the technology that underpins communication on the internet and is used to access websites, stream media, play games, and much more. All devices that connect to the internet will use IP addresses to connect to and communicate with other servers and devices.
What does an IP address look like?
IP addresses were originally created by ARPANET in 1983. They used a 32-bit number divided into 4 segments, which can range from 0.0.0.0 to 255.255.255.255. These are referred to as IPv4 addresses.
The Internet Assigned Numbers Authority (IANA) is in charge of assigning and managing address spaces. Since 1983, global internet usage and the number of devices capable of accessing the internet is many times larger than it was when IP addresses were first envisioned. The world is running out of available IPv4 address spaces, and so IPv6 was created to help increase capacity.
IPv4 vs IPv6
IPv6 was created in the mid-to-late ‘90s and has been slowly rolling out across the internet ever since. IPv6 uses a 128-bit address space and looks something like this: 2001:db8:0:1234:0:567:8:1
Though most devices now support both IPv4 and IPv6 style addresses, adoption of IPv6 is slow and IPv4 addresses are still more commonly used. This will inevitably change given the dwindling finite available IPv4 spaces, but for now, they remain the most common. This is because the two formats are not interoperable, so IPv4 addresses are not easily replaced with newer IPv6 addresses.
The semantic structure of IP addresses
IP addresses are subdivided into a number of components. A typical IPv4 address will have 4 sets of digits and three zeroes, such that it looks something like: x.x.x.x
Netmask and network size
A netmask helps divide an IP address up into subnets. This is useful for large organizations that need many nodes, and also for network management purposes.
As an example, an IP address of 192.0.0.7 with a netmask of 255.255.255.255 will only refer to 192.0.0.7. However, a netmask of 255.255.255.0 can apply to a range of IPs from 192.0.0.0 to 126.96.36.199. Likewise, a netmask of 255.255.0.0 can apply to IPs ranging from 192.0.0.0 to 188.8.131.52.
Network classes for IPv4
Each set of digits in an IP address represents network classes and nodes, which are referred to as Class A, Class B, and Class C. Class A addresses have a large number of network nodes, and each subsequent class has fewer nodes available.
In class A, the structure of an IP address looks like: network.node.node.node
In class C, the structure of an IP address looks like: network.network.network.node
Benefits of using IPv6
IPv6 offers a number of benefits over IPv4, though unfortunately, the two formats are not interoperable. This has resulted in a slower adoption rate, but the benefits will eventually lead to widespread adoption given enough time.
The primary benefit is the increased address space capacity. The IPv4 address space has a maximum of 4.3 billion unique addresses. In contrast, IPv6 address space size is 2128, a number 39 digits long. This provides enough capacity for every living person to have a unique IP address for all their devices, several times over.
Other benefits of IPv6 over IPv4 include increased packet payloads (the amount of data that can be sent in a single payload), optimized packet headers for quicker and easier routing, and future-proofing extension headers, which enable further optimizations and features to be added in the future.
Importance for search engine optimization
IP addresses generally do not have an effect on SEO, but they can be important with regard to backlinks. A backlink is a link from another website to your website. They are also known as incoming links or inbound links. Backlinks are very important for search engine rankings, as many search engines such as Google use them for prioritizing results (among many other factors). Each link from an outside website to your website can be considered a "vote", and the more votes a website has, the more popular it must be.
An old trick to manipulate search engine results used by less scrupulous webmasters was to create additional dummy websites, whose sole purpose was to generate backlinks for their main website. This is detectable and blockable by most search engines.
The IP address is one way in which search engines can identify such artificial backlinks. If many backlinks to a website can be traced to one IP address, it may be a sign that those are artificial backlinks, and their influence on search engine results will be reduced.