FRITZ!Box 3390 Service - Baza wiedzy

FRITZ!Box 3390 Service
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Error message "The port forwarding cannot be created or enabled [...]".

You cannot configure port forwarding in the FRITZ!Box. When you try to configure port forwarding, one of the following error messages is displayed:

  • "Port forwarding cannot be configured or enabled, because there is already a corresponding port forwarding setting."
  • "Port forwarding cannot be configured or enabled because the rules conflict with an internal rule."
  • "The port forwarding cannot be created or enabled, because the port is already in use for remote maintenance (HTTPS) (Internet / Permit Access / FRITZ!Box Services)."
  • "Port forwarding cannot be created or enabled because Internet access to your storage media over FTP/FTPS is enabled (Internet / Permit Access / FRITZ!Box Services)."


  • You are trying to set up a second port forwarding rule for a TCP or UDP port, or for the IP protocols ESP or GRE in the FRITZ!Box. However, as a rule it is not possible to configure multiple port forwarding rules for the same port or for the IP protocols ESP or GRE in a network router like the FRITZ!Box.

    Note:The FRITZ!Box checks all incoming and outgoing data packets and automatically rejects unrequested data from the Internet (Stateful Packet Inspection). The FRITZ!Box uses the NAT (Network Address Translation) mechanism to check incoming data and determine which port they are addressed to, which IP protocol they are transporting, and which device they are to be forwarded to. If ports or IP protocols are forwarded more than once, it is no longer clear which device the data is for. Therefore, it is not possible to configure multiple forwarding rules with NAT.

1 Ports used by the FRITZ!Box

The FRITZ!Box itself uses some ports to provide functions such as Internet telephony. Here we give you an overview of ports that are typically opened by FRITZ!Box services:

Note:You can find a list of all the ports being used by your FRITZ!Box in the user interface under "Diagnostics > Security".

  • TCP port 21 (Internet access to storage media via FTP/FTPS)
  • TCP port 443 (MyFRITZ! or Internet access to the user interface via HTTPS)
  • UDP ports 500 and 4500 (VPN)
  • TCP and UDP port 5060 (Internet telephony)
  • UDP ports 7078-7109 (Internet telephony)
  • TCP port 8089 (automatic configuration over TR-069)

2 Using a different port

If several network devices (for example computers, NAS systems, game consoles) or Internet applications such as chat software or online games require the same TCP or UDP port for incoming connections from the Internet, configure the devices or applications so that they all use different ports:

Important:IP protocols ESP and GRE can only be forwarded for one device. There is no workaround for these IP protocols.

  1. Configure the network device or Internet application so that connections from the Internet are received by ports that are not used by the FRITZ!Box, other network devices, or other Internet applications.

    Important:If you use the same application on several computers, assign different ports for incoming connections in the application on each computer.

  2. Configure port forwarding rules in the FRITZ!Box for the new ports you configured in the network device or the Internet application.

Now all of the network devices or Internet applications for which you configured port forwarding can accept connections from the Internet.