FRITZ!Box 4020 Service - Knowledge Base

FRITZ!Box 4020 Service

Setting up the FRITZ!Box for use with a cable connection

The FRITZ!Box is already configured for use with a cable modem in the factory settings. You only have to connect the FRITZ!Box to the cable modem, and then you can access the internet using the FRITZ!Box without having to configure any settings first. Since the FRITZ!Box controls the internet access, all FRITZ!Box functions (such as the firewall, parental controls) are also available without restriction in this operating mode.

If you changed the settings of the FRITZ!Box, configure the FRITZ!Box for use with a cable modem as described in this guide.

Requirements / Restrictions

  • Internet access on the FRITZ!Box's WAN port is limited to 90 to 93 Mbit/s.

    Important:If you have a cable connection with speeds exceeding 100 Mbit/s, we recommend using a FRITZ!Box Cable or a FRITZ!Box with gigabit LAN. You can find information on current FRITZ!Boxes in the product section of our homepage.

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

1 Connecting a cable modem

  1. Either connect the cable modem to the first multimedia socket or to the socket that the cable technician used for the original installation. Only use the coaxial cable (without an extension) provided by the cable technician to connect it.

2 Configuring the cable modem

Instead of cable modems, some cable providers supply their customers with wireless cable routers with integrated cable modems. These devices can provide their own wireless network and have several LAN ports for computers, game consoles, and other devices.

The following step is only necessary if you are using a wireless cable router, but are not using the cable router's wireless network:

  1. If possible, enable the so-called bridge mode for the wireless cable router in your cable provider's customer center or in the cable router's user interface.

    Note:In bridge mode, the cable router acts as a simple cable modem, so you will not experience problems when accessing the FRITZ!Box user interface from the internet, for example. You may not be able to use hotspot services offered by your cable provider when bridge mode is enabled.

3 Configuring the FRITZ!Box


  1. If the FRITZ!Box is connected to the cable modem, clear the connection between the cable modem and the FRITZ!Box, then restart the cable modem.

    Note:You can restart the cable modem by briefly unplugging it. It may take several minutes for the cable modem to restart.

Configuring internet access

  1. Open the FRITZ!Box user interface.
  2. Enter the FRITZ!Box password on the underside of the device and click "Log In". If the FRITZ!Box is set to factory settings:
    1. Select the desired user interface language and click "Next".
    2. Select your country from the drop-down list and click "Next". If your country is not listed, select "Other country".
  3. Click "Internet" and then "Account Information".
  4. Select "Cable modem or internet router" from the drop-down list "Internet connection via".
  5. Enter the speeds of your internet connection in the "Downstream" and "Upstream" fields.
  6. Use a network cable to connect the cable modem to the "WAN" port on the FRITZ!Box and click "Apply" to save the settings.

Now the FRITZ!Box establishes its internet connection over the cable modem. Configuration is completed when the message "The procedure was concluded successfully" is displayed.