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Knowledge document #894

Setting up automatic port sharing in the FRITZ!Box

By default, the FRITZ!Box's firewall blocks all incoming connections from the internet. If some of the internet applications (for example chat software, online games, file-sharing software) you use require port sharings for incoming connections from the internet, you can configure the FRITZ!Box so that the network device on which the internet application is running can set up the necessary port sharing settings by itself if required.

The port sharings are only set up for the period of time during which the application requires them, and then the FRITZ!Box disables them again.

Requirements / Restrictions

  • The FRITZ!Box must either obtain an IPv6 address or a public IPv4 address from the internet service provider.
  • The mobile network provider must allow incoming connections to the FRITZ!Box.

    Important:Many mobile network providers block incoming connections or only allow ones with special contracts.

Note:All instructions on configuration and settings given in this guide refer to the FRITZ!Box 6820 LTE v2 and v3 with the latest FRITZ!OS, the FRITZ!Box 6820 LTE v1 may vary.

1 Configuring the FRITZ!Box for automatic port sharing

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Network" in the "Home Network" menu.
  3. Click on the "Network Connections" tab.
  4. Click the (Edit) button next to the device you want to configure.
  5. Enable the option "Permit independent port sharing for this device" in the "Permit Access" section.
  6. Click "Apply" to save the settings.

2 Configuring the application for automatic port sharing

  1. Configure the application so that it uses PCP or UPnP. Refer to the manufacturer for information on how to set it up, for example consult the manual.

3 Configuring the device's firewall

If the application is installed on a device with its own firewall (for example Windows firewall), the firewall must also be configured:

Important:If you allow devices to set up port sharing themselves, malware could also set up port sharing on these devices and thus bypass the FRITZ!Box's firewall. You should therefore set up a firewall on these devices for security reasons.

  1. Configure the device's firewall according to the manufacturer's instructions so that the server service or application can be accessed.

Now applications can automatically open the required ports in the FRITZ!Box.

Ports currently opened are shown under "Internet > Permit Access" and "Diagnostics > Security" in the FRITZ!Box user interface.



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