An Internet Protocol (IP) Address is a unique sequence of numbers, separated by full stops. These numbers identify every device using an internet connection. An IP address acts like a phone number, allowing devices to send and receive data from other devices. There are public and private IP addresses, which can either be static or dynamic.
- Public IP address: a public IP address is the primary IP address connected to a home or business network. This IP address connects you to the internet and is globally unique to your router.
- Private IP address: private IP addresses are used to communicate within the same network, such as an intranet. Several devices within a home or organization will have private IP addresses, which are then connected to the router’s public IP address for internet access. A private IP address will remain hidden when connected to the internet, while the router’s public IP address is visible.
- Static IP address: a static IP address (or fixed IP) is a permanent number, which is assigned manually to a computer or router. Static IP addresses do not change automatically, making it useful for other devices to know exactly how to contact the device using one. Static IP addresses are typically used by servers and other important business equipment.
- Dynamic IP address: most IP addresses assigned by an internet service provider will be dynamic. It is more cost effective for a provider to allocate dynamic IP addresses to customers. Dynamic addresses are subject to change automatically over time, and are assigned as needed by Dynamic Host Configuration Protocol (DHCP) servers.
- White-listed IP address: White-listed IP addresses are implemented as a security feature that have been given exclusive access to a firewall. Often used to limit control to only trusted users and devices, white-listed IP address filters to other IP addresses that have been explicitly approved to access a domain.