FRITZ!Box 4020 Service - Knowledge Base

FRITZ!Box 4020 Service

Internet connection is slow

The Internet connection on computers, smartphones, and other devices connected to the FRITZ!Box is very slow. As a result, web pages load slowly, it takes a long time to download files, and video streams are either not displayed correctly or stop playing, for example.

Note:The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS for your FRITZ!Box.

Simply proceed as described below. After each measure, check whether the issue persists.

1 Restarting the modem or router

The modem or upstream router may be malfunctioning, for example due to an error that occurs occasionally:

  • Restart the modem or router by unplugging the device briefly.

    Note:It may take several minutes for the modem or router to restart. While it is restarting you will not be able to access the Internet.

2 Setting the speed of your Internet connection in the FRITZ!Box

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. In the "Connection Settings" section, enter the speed for receiving files (download) supported by your Internet connection in kbit/s (for example 50000 for 50 Mbit/s) in the "Downstream" field.
  4. In the "Upstream" field, enter the speed for sending data (upload) supported by your Internet connection in kbit/s (for example 5000 for 5 Mbit/s).
  5. Click "Apply" to save the settings.
  6. Test whether the speed of your Internet connection is now sufficient.
    • If Internet access is now significantly faster:
      • Proceed with the following section.
    • If Internet access is still much too slow:
      • Reduce the upstream value by 100 kbit/s and then test whether the speed of your Internet connection is now sufficient. Repeat this procedure several times and use the setting that gives you the best speed.

3 Checking the throughput between the wireless device and the FRITZ!Box

Perform the following step if the device is connected to the FRITZ!Box over wireless LAN, but it also is equipped with a network port:

  1. Clear the wireless connection between the device and the FRITZ!Box.
  2. Use a network cable (for example the yellow cable included with delivery) to connect the device to the FRITZ!Box.
  3. Check whether you notice any difference in speed when you connect to the Internet over LAN instead of over wireless LAN.

4 Correcting the Windows network settings

In order for a computer to access the Internet, all Internet requests from the computer must be forwarded to the FRITZ!Box. If the computer automatically obtains its IP settings from the FRITZ!Box via DHCP, then it also automatically obtains a default gateway (IP address of the FRITZ!Box).

Multiple default gateways are not allowed and cause errors. Therefore, make sure that only one single standard gateway is configured:

Note:Note for network experts: Default gateways required to route to another IP network can be replaced with a static route. Refer to the Windows help for information on how to set up static routes.

  1. Press the keyboard shortcut "Windows key" + "R".
  2. Enter cmd in the "Open" field and click "OK".
  3. Enter route print in the command prompt window and press Enter.
  4. Check how many entries in the table start with 0.0.0.0.
  5. If there is more than one standard gateway (several entries begin with 0.0.0.0):

    Windows 10 / 8:

    1. Press the keyboard shortcut "Windows key" + "X" and select "Control Panel" from the context menu.
    2. Click "Network and Internet" in the "Control Panel" menu.
    3. Click "Network and Sharing Center" and then "Change adapter settings".
    4. Click on the arrow next to the button (Change view) in the menu bar and select "Details".
    5. Right-click the LAN connection for a network adapter that is not connected to the FRITZ!Box. The name of the network adapters is listed under "Device Name".
    6. Click "Properties".
    7. Select "Internet Protocol Version 4 (TCP/IPv4)".
    8. Click "Properties".
    9. If there is a default gateway entry, remove it.
    10. Click "OK" to save the settings.

    Windows 7:

    1. In Windows, click "Start" and then "Control Panel".
    2. Select "Category" from the drop-down list "View by:" on the top right ().
    3. Click "Network and Internet" and then "Network and Sharing Center".
    4. Click "Change adapter settings".
    5. Click on the arrow next to the "Change view" button in the menu bar and select "Details".
    6. Right-click the LAN connection for a network adapter that is not connected to the FRITZ!Box. The name of the network adapters is listed under "Device Name".
    7. Click "Properties".
    8. Select "Internet Protocol Version 4 (TCP/IPv4)".
    9. Click "Properties".
    10. If there is a default gateway entry, remove it.
    11. Click "OK" to save the settings.
  6. Repeat these steps for all LAN connections of network adapters that are not connected to the FRITZ!Box.

5 Configuring security software

Using security software such as firewalls, antivirus software or web filters to monitor Internet access can reduce the Internet speed on your computer:

  • Configure all security software installed so that it does not limit the speed of your Internet connection.

Now the FRITZ!Box and the devices connected to it establish the fastest Internet connection possible. If Internet access continues to be slow, your Internet service provider may be experiencing technical difficulties, or there may be an issue with the upstream modem or router.