To the knowledge base
Dokument informacyjny #339

IP communication over a VPN connection (client-LAN) is not possible

Although the device (for example a computer with FRITZ!VPN) establishes a VPN connection to the remote FRITZ!Box, the device cannot access devices, shared files, and printers or other services in the remote network. Devices in the remote network do not respond to pings.

Simply proceed as described below. After each measure, check whether the problem is solved.

1 Adjusting the network settings

VPN communication is not reliable if an IP address from the remote FRITZ!Box's IP network is assigned to the computer's LAN or wireless network adapter. VPN communication may even be disrupted if the network adapter is not used at all.

Example:
If the remote FRITZ!Box uses the IP address 192.168.178.1 (subnet mask 255.255.255.0), no network adapters may be assigned an address from the 192.168.178.xxx range.

On the computer, disable all network adapters that have an IP address from the remote FRITZ!Box's IP network:

Windows 10

  1. Click (Start) and then (Settings) in the Windows task bar.
  2. Click "Network & Internet" in the "Settings" menu.
  3. Click "Change adapter options" in the section "Change your networking settings".
  4. Right-click the respective network connection and select "Disable" from the context menu.

Windows 8

  1. Press the keyboard shortcut Windows key + X and select "Control Panel" from the context menu.
  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. Right-click the respective network connection and select "Disable" from the context menu.

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. Right-click the respective network connection and select "Disable" from the context menu.

macOS

  1. Open the Finder and click "Applications".
  2. Click "System Preferences" and "Network".
  3. On the left side, select the respective network adapter.
  4. Click the gear symbol next to the plus and minus (+/-) symbols and select "Make Service Inactive".
  5. Click "Apply" to save the settings.

2 Restarting the FRITZ!Box

You may be temporarily unable to correctly establish the VPN connection due to an error in the FRITZ!Box or its internet connection. Therefore, restart the FRITZ!Box so that it reinitializes the firewall and re-establishes the internet connection:

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Backup" in the "System" menu.
  3. Click on the "Restart" tab.
  4. Click the "Restart" button.

3 Adjusting the VPN settings

If you establish the VPN connection with the FRITZ!VPN software, data cannot be exchanged over the VPN connection if incorrect or unsuitable IP settings were entered when generating the VPN settings. For example, this is the case if:

  • the FRITZ!Box uses the IP network 192.168.100.0 reserved for the cable provider in compliance with DOCSIS,
  • the FRITZ!Box's IP address (xxx.xxx.xxx.1) was entered as the "destination network" in FRITZ!VPN instead of its IP network (xxx.xxx.xxx.0),
  • the "IP address of the user in the FRITZ!Box network" lies in the DHCP range of the FRITZ!Box or is already being used for another VPN connection (for example for a smartphone).

To correct errors in the VPN settings, reconfigure the connection:

  1. Delete the VPN connection in the Configure FRITZ!Box VPN Connection software.
  2. Delete the VPN connection in the FRITZ!VPN software and in the FRITZ!Box.
  3. Reconfigure the VPN connection between FRITZ!VPN and the FRITZ!Box.