IP address
An IP address serves two principal functions. It identifies the host, or more specifically its network interface, and it provides the location of the host in the network, and thus the capability of establishing a path to that host. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."
The header of each IP packet contains the IP address of the sending host, and that of the destination host.
IP address
A host may use geolocation software to deduce the geolocation of its communicating peer.
A public IP address, in common parlance, is a globally routable unicast IP address, meaning that the address is not an address reserved for use in private networks, such as those reserved by , or the various IPv6 address formats of local scope or site-local scope, for example for link-local addressing. Public IP addresses may be used for communication between hosts on the global Internet.