When configured for operation as a router, the FRITZ!Box manages all IP connections to the internet so that it can forward responses from remote sites to the correct devices in the home network. FRITZ!Box does not limit the number of simultaneous IP connections.

Since the maximum number of IP connections depends on the usage of the FRITZ!Box's memory, in practice it can differ according to the other functions being used at a given time (such as wireless LAN, telephony). According to experience, it is possible to have several hundred simultaneous IP connections.