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Optimizing the FRITZ!Box's settings for "WiFi-Calling"

"WiFi Calling" is a mobile network option offered by a number of mobile network providers that allows their customers use telephony over Wi-Fi (VoWifi). With VoWifi, mobile calls can be made over any Wi-Fi network. To use VoWifi you only need a compatible mobile telephone and Wi-Fi access to the internet.

In the following we show how to optimize the FRITZ!Box settings for "WiFi Calling".

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

1 Configuring prioritization for telephony via Wi-Fi

Links "Help and Info" and then "FRITZ!Box Support"
  1. In the FRITZ!Box user interface, click "Help and Info" on the bottom left of the page and then on "FRITZ!Box Support" at the bottom.
  2. Enable prioritization in the section "Upstream VoWifi prioritization for epdg.epc.*.3gppnetwork.org".
  3. Click "Apply setting" to save the settings.

2 Configuring the DNS server of the internet service provider

Some internet service providers, for example Vodafone, only allow the use of VoWifi if the DNS servers assigned by the internet service provider are used. If you set up other DNS servers in the FRITZ!Box, for example Google Public DNS, re-enable the DNS server of the internet service provider:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. Click on the "DNS Server" tab.
  4. Enable the option "Use DNSv4 servers assigned by the internet service provider (recommended)".
  5. If the section "DNSv6 Servers" is displayed, enable the option "Use DNSv6 servers assigned by the internet service provider (recommended)".
  6. If the option "Encrypted name resolution in the internet (DNS over TLS)" is enabled, enable the option "Allow fallback to non-encrypted name resolution in the internet".
  7. Click "Apply" to save the settings and on the FRITZ!Box, confirm that the procedure may be executed, if you are asked to do so.

3 Configuring guest access for telephony via Wi-Fi

The following step is only necessary if you also want to make VoWifi available in the guest network:

  1. Click "Wi-Fi" ("Wireless") in the FRITZ!Box user interface.
  2. Click "Guest Access" in the "Wi-Fi" menu.
  3. Enable guest access so you can configure settings.
  4. Click "Additional Settings" further below.
  5. Disable the option "Restrict internet applications".