In order for computers, smartphones, and other network devices to communicate with each other, each device must be addressable via a unique IP address. For communication on the internet, the FRITZ!Box obtains an IP address from the internet service provider when it connects to the internet.

If Internet Protocol version 4 (IPv4) is used, each IP address can be associated with 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) over the internet, devices with IP addresses from private IP address ranges cannot be accessed from the internet.

    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 at a time worldwide. 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.