FRITZ!Box 7390 – Service - Knowledge Base

FRITZ!Box 7390 – Service

Slow Internet access when FRITZ!Box establishes the Internet connection via DSL

The Internet connection of a network device (for example a computer, smartphone) 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 are interrupted. In this case, the FRITZ!Box itself establishes the Internet connection (standard).

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 Checking the DSL line

Checking the throughput of the DSL connection

Check whether the FRITZ!Box displays the DSL throughput (speed) guaranteed by your DSL provider:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "DSL Information" in the "Internet" menu.
  3. The actual DSL speed is displayed on the "DSL" tab in the "Current throughput" line. Compare this throughput with the speed guaranteed by your provider.
    • If the current throughput is almost as high as the speed guaranteed by your DSL provider, then there is no problem.

      Note:With many DSL lines, you will not be able to fully achieve the guaranteed throughput. Therefore, DSL providers say that they offer DSL speeds of "up to" a certain value.

    • If the current throughput is significantly lower:

Checking the DSL connection for errors

Problems with the DSL line may slow down the Internet connection. Therefore, check whether numerous errors occur on your DSL line:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "DSL Information" in the "Internet" menu.
  3. Click on the "DSL" tab.
  4. Check in the "Error Counter" section whether "Not Remediable Errors" (CRC) occur in the FRITZ!Box or the DSL exchange when you use the Internet.

2 Checking the throughput between the computer and the FRITZ!Box

The following step is only necessary if the computer is connected to the FRITZ!Box over wireless LAN:

  1. Clear the wireless connection between the computer and the FRITZ!Box.
  2. Use a network cable (for example the yellow cable included with delivery) to connect the computer to the FRITZ!Box.
  3. Check whether Internet access over LAN is exactly as slow as when the computer was connected over wireless LAN.

3 Correcting the Windows network settings

In order for a network device to access the Internet, all Internet requests from the network device must be forwarded to the FRITZ!Box. If the network device is configured to automatically obtain an IP address, it automatically obtains a default gateway (IP address of the FRITZ!Box) from the FRITZ!Box's DHCP server for this purpose.

The configuration of multiple default gateways on a network device is not allowed and causes errors. Therefore, check whether more than one default gateway has been configured and remove any default gateways that are not connected to the FRITZ!Box:

Note:Note for network experts: Default gateways required for routing to another known IP network can be replaced with a static route. The Windows help contains information on configuring 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 "Change view" icon 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:" (top right) in the "Control Panel" menu.
    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" icon 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.

4 Disabling IPv6 support in macOS

If the Internet connection uses the DS-Lite ("Dual Stack Lite") procedure, you may experience interruptions and delays when opening web pages on computers with macOS. You can solve this problem by disabling IPv6 support in macOS:

Note:With DS-Lite you can still use IPv4 applications with IPv6 Internet connections. When DS-Lite is active, the status "IPv4 over DS Lite" is displayed under "Connections" on the "Overview" page of the FRITZ!Box user interface.

5 Configuring security software

The use of security software (such as a firewall, antivirus software, web filter) to monitor Internet access can reduce the Internet speed on your computer:

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

    Note:You can find information on configuring the security software in its manual, or consult its manufacturer directly.

6 Loading the factory settings and reconfiguring the FRITZ!Box

If Internet access continues to be very slow, then your FRITZ!Box settings are inconsistent. In this case you must completely reconfigure the FRITZ!Box:

Saving the telephone book

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Book" in the "Telephony" menu.
  3. Select a telephone book, click the "Save" button and save the telephone book as an XML file on your computer.
  4. Repeat these steps to save each of the telephone books configured in the FRITZ!Box.

Loading the factory settings

Important:Once the procedure is finished, do not use a previously saved "fritzbox[...].export" file to restore any settings as this may cause Internet access to be slow again.

Configuring the FRITZ!Box

  • Completely reconfigure the FRITZ!Box.

Restoring the telephone book

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Book" in the "Telephony" menu.
  3. If you would like to transfer the telephone book you saved to a new telephone book, click on the "New Telephone Book" link. However, the options "Quick-dial number", "Vanity code" and "Important person" are only available for the first telephone book,
    • or, if you would like to replace an existing telephone book:
      • Click on the "Switch telephone books" link and select a telephone book from the list. All of the existing telephone book entries are overwritten when the telephone book is restored.
  4. Click the "Restore" button.
  5. Click the "Choose File" button and select the file (*.XML) with the telephone book you saved.
  6. Click the "Restore Telephone Book" button.
  7. One after another, restore all of the telephone books you would like to use.

Now the FRITZ!Box and network device establish the fastest Internet connection possible. We are not aware of any further measures for this issue. Another cause could be technical difficulties your Internet service provider may be experiencing. In this case, the FRITZ!Box cannot resolve this issue.