For computers, smartphones, and other network devices to able to communicate with each other, each device must be addressable using a unique IP address. When the FRITZ!Box connects to the internet, your cable provider assigns it an IP address for communication on the internet.

When using Internet Protocol version 4 (IPv4), each IP address can be assigned to one of the following address ranges:

• Private address ranges:
  • IP addresses from private address ranges are intended exclusively for communication in private networks (for example the FRITZ!Box home network) and can therefore be used in an unlimited number of networks at the same time. Since they are never forwarded (routed) on the internet, devices cannot be accessed from the internet if they have IP addresses that belong to private address ranges.

    Note:For more information on "private addresses", see Wikipedia.

• Public address ranges:
  • IP addresses from public address ranges are only used by a single device worldwide at a time. Since they make it possible to unequivocally identify network devices, they are forwarded on the internet (routed) and therefore allow the network devices to be accessed from the internet.