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Knowledge document #894

Setting up automatic port sharing via UPnP

By default, the FRITZ!Box's firewall blocks all incoming connections from the internet. If you enable the FRITZ!Box's UPnP function, internet applications (for example chat software, online games, file-sharing software) can automatically adjust the FRITZ!Box's security settings and set up the necessary port sharing settings by themselves.

Requirements / Restrictions

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Configuring the FRITZ!Box for automatic port sharing

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Home Network Overview" in the "Home Network" menu.
  3. Click on the "Network Settings" tab.
  4. Enable the option "Transmit status information over UPnP". If the option is not displayed, enable the Advanced View first.
  5. Click "Apply" to save the settings.
  6. Click "Internet" and then "Permit Access".
  7. Click on the "Port Sharing" tab.
  8. Enable the option "All devices in the home network are allowed to change their own port sharing settings".
  9. Click "Apply" to save the settings.

2 Configuring an application to use UPnP

  1. Configure the application so that it uses 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 changing the security settings via UPnP is allowed, malware can also cause ports to be shared, thus bypassing the FRITZ!Box's firewall. You should therefore set up a firewall on all computers in the home network for security reasons.

  1. Configure the device's firewall according to the manufacturer's instructions to allow access to the server service or application from the FRITZ!Box home network.

Now UPnP-capable applications automatically open the required ports in the FRITZ!Box.

You can find a current overview of ports automatically enabled for port sharing in the FRITZ!Box user interface under "internet > Permit Access > Port Sharing" in the section "List of Shared Ports". You can click the (Delete) button to manually close individual ports.