What is an IP address?

An IP address (Internet Protocol address) is the number that identifies a device on a network, so that data can be delivered to it, like a postal address for computers. Inside an office, devices usually have private addresses such as 192.168.1.20, which are not reachable from the internet directly; the router has a public address that the outside world sees. Addresses can change when a device reconnects, which is why security tools also record a device's name or hardware address. When an alert names an IP address, the first step is usually to find out which device had that address at that time.

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