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Using FRITZ!VPN to access multiple IP networks behind a FRITZ!Box

With the FRITZ!VPN software you can establish a secure VPN (Virtual Private Network) connection from a Windows computer to your FRITZ!Box via the internet and access all of the network devices and services in the FRITZ!Box home network.

If there is another network router in the FRITZ!Box home network that connects the IP network of that FRITZ!Box to a second IP network, you must configure additional settings to be able to access network devices in the second IP network over the VPN connection.

Example values used in this guide

In this guide we show you how to use FRITZ!VPN to configure VPN access to another IP network behind the remote FRITZ!Box. When adjusting the connection settings, replace the values used in this example with actual values.

  • IP network of the FRITZ!Box:
    192.168.20.0 (subnet mask: 24 - 255.255.255.0)
  • IP address of the computer with FRITZ!VPN in the FRITZ!Box network:
    192.168.20.201
  • IP network of the network router connected to the FRITZ!Box:
    192.168.21.0 (subnet mask: 24 - 255.255.255.0)
  • IP addresses of the network router in the FRITZ!Box network:
    192.168.20.2 and 192.168.21.1

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

1 Adjusting the VPN settings for FRITZ!VPN

  1. Start the Configure FRITZ!Box VPN Connection software.
  2. In the "Existing Configurations" window, click the plus sign in front of the FRITZ!Box's MyFRITZ! domain name (pi80ewgfi72d2os42.myfritz.net) and select the email address of the VPN user (john@smith.com) who should access the IP network of the network router connected to the FRITZ!Box.
  3. Click "Explorer" and open the file named "vpnuser_[...].cfg" with a text editor, for example WordPad.
  4. Look for the entry "accesslist" and add the IP network of the network router connected to the FRITZ!Box to this entry:
    • accesslist =
    • "permit ip any 192.168.20.0 255.255.255.0",
    • "permit ip any 192.168.21.0 255.255.255.0";

      Important:The entries for the IP networks must be separated by a comma and the value for "accesslist" must end with a semicolon.

  5. Save the changes and import the edited file "vpnuser_[...].cfg" to FRITZ!VPN.

2 Configuring the FRITZ!Box

Adjusting the FRITZ!Box's VPN settings

  1. Start the Configure FRITZ!Box VPN Connection software.
  2. In the "Existing Configurations" window, select the the FRITZ!Box's MyFRITZ! domain name (pi80ewgfi72d2os42.myfritz.net) and click on "Explorer".
  3. Open the file named "fritzbox_[...].cfg" with a text editor (for example WordPad).
  4. Search for the section where the email address of the VPN user (john@smith.com) who should access the IP network of the network router connected to the FRITZ!Box is given by the "name" entry.
  5. Look for the entry "accesslist" in this section and add the IP network of the network router connected to the FRITZ!Box to this entry:
    • accesslist =
    • "permit ip 192.168.20.0 255.255.255.0 192.168.20.201 255.255.255.0",
    • "permit ip 192.168.21.0 255.255.255.0 192.168.20.201 255.255.255.0",

      Important:The entries for the IP networks must be separated by a comma and the value for "accesslist" must end with a semicolon.

  6. Save the changes and import the edited file "fritzbox_[...].cfg" to the FRITZ!Box.

Configuring a static IP route in the FRITZ!Box

Configure a static IP route in the FRITZ!Box to allow network devices in the FRITZ!Box's IP network (192.168.20.0/24) to access the IP network of the network router connected to the FRITZ!Box (192.168.21.0/24):

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Network" in the "Home Network" menu.
  3. Click on the "Network Settings" tab.
  4. Click "Additional Settings" in the section "Guest Access" to display all of the settings.
  5. Click "IPv4 Routes".
  6. Click "New IPv4 Route".
  7. Enter the IP network of the network router connected to the FRITZ!Box (192.168.21.0) as the "IPv4 network".
  8. Enter the subnet mask of the other IP network (255.255.255.0) in the "Subnet mask" field.
  9. For the "Gateway", enter the IP address of the network router in the FRITZ!Box home network (192.168.20.2) that connects the two IP networks.
  10. Enable the option "IPv4 route active".
  11. Click "OK" to save the settings.

3 Adjusting additional IP settings for the VPN connection

Configuring the IP route in the network router

  1. Configure the network router according to the manufacturer's instructions so that it routes between the FRITZ!Box's IP network (192.168.20.0) and its own IP network (192.168.21.0).

    Note:If a Windows computer with several network adapters is used as the router, "IP routing" must be enabled in Windows. Refer to Microsoft for information on how to set it up.

Configuring network devices in the network router's IP network

  1. Either: On the devices, configure the IP address of the network router from its own IP network (192.168.21.1) as the default gateway.
    • Or: On the devices, configure a static IP route to the IP network of the FRITZ!Box (192.168.20.0) that uses the network router as the gateway (192.168.21.1).