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Knowledge document #3749

Checking accessibility of the FRITZ!Box in the internet

To access the FRITZ!Box via the internet, the FRITZ!Box must have an IPv6 or IPv4 address that can be reached in the internet. The device that is to access the FRITZ!Box must also be able to access this IP address.

Whether the FRITZ!Box has an IPv6 or IPv4 address that can be reached in the internet depends on the FRITZ!Box's internet connection. Whether the device that is to access the FRITZ!Box can access the FRITZ!Box's IP address depends in turn on the internet connection of the device.

Depending on the type of both of the internet connections, the FRITZ!Box is either only reachable via IPv6, via IPv6 and IPv4, only via IPv4, or not reachable in the internet at all.

Internet connectionAccessible in the internet via IPv6?Accessible in the internet via IPv4?
IPv4 (without IPv6)  -  ✓
IPv6 (without IPv4)  ✓ -
IPv6 with MAP-T ✓ Only via certain points stipulated by the internet provider
IPv6 with MAP-E ✓ Only via certain points stipulated by the internet provider
IPv6 with Lightweight 4over6  ✓ Only via certain points stipulated by the internet provider
IPv6 + IPv4 via carrier-grade NAT ✓ -
Dual Stack (IPv6 + IPv4)  ✓ ✓
DS-Lite tunnel (IPv6 + IPv4 without a public IPv4 address) ✓ -
DS-Lite tunnel with PCP (Port Control Protocol) ✓ Only via certain points stipulated by the internet provider
Mobile network Mobile network providers usually block incoming connections Mobile network providers usually block incoming connections

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

1 Checking the FRITZ!Box's IP addresses

Whether the FRITZ!Box has an IPv6 or IPv4 address that can be reached in the internet depends on which IP addresses the internet provider assigns the FRITZ!Box when it connects to the internet:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click on "Online Monitor" in the "Internet" menu.
  3. Click the "Connection Details" tab.
  4. Check which addresses are displayed in the lines "Internet, IPv4" and "Internet, IPv6".
  5. If an IPv6 address is displayed, the FRITZ!Box can be reached in the internet via IPv6.
  6. If no IPv4 address is shown or an IPv4 address from one of the following ranges is displayed, the FRITZ!Box cannot be reached via IPv4 in the internet.
    • 10.0.0.0 - 10.255.255.255
    • 100.64.0.0 - 100.127.255.255 (carrier-grade NAT)
    • 172.16.0.0 - 172.31.255.255
    • 192.0.0.0 - 192.0.0.7 (DS-Lite tunnel, Dual-Stack Lite)
    • 192.168.0.0 - 192.168.255.255
    • If an IPv4 address from a different range is displayed, the FRITZ!Box has a public IPv4 address and can be reached via IPv4 in the internet.

      Important:If the message "Your internet provider makes the following ports available: [...]" is displayed under "Other Connections > Port Sharing", the FRITZ!Box is only reachable over these ports via IPv4.

2 Checking the device's internet connection

Whether a device can also access an IPv6 or IPv4 address of the FRITZ!Box that can be reached in the internet depends on the internet connection of the device and can vary depending on the location (for example mobile network, Wi-Fi hotspot):

  1. Call up test-ipv6.com or ipv6-test.com on the device at the location where you wish to access the FRITZ!Box.
  2. If the test result shows that IPv6 connectivity is available and that the FRITZ!Box has an IPv6 address, the device can access the FRITZ!Box in the internet via IPv6.
  3. If the test result shows that IPv4 connectivity is available and that the FRITZ!Box has a public IPv4 address or is used with a DS-Lite tunnel with PCP, the device can access the FRITZ!Box in the internet via IPv4.

    Note:If the device can reach the FRITZ!Box via IPv6 as well as IPv4, it usually automatically uses the IP protocol that is faster at that particular time.

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