FRITZ!Box 4020 Service - Knowledge Base
Using VPN software from another manufacturer in the home network
You can also use VPN software from another manufacturer to establish VPN connections to remote VPN servers over the FRITZ!Box's Internet connection. No special settings are required because VPN passthrough is enabled for the VPN protocols IPSec and PPTP in the FRITZ!Box by default.
If the VPN software uses the IPSec protocol without NAT traversal or the PPTP protocol, the following restrictions apply:
- It is not possible for several VPN clients in the FRITZ!Box home network to establish connections to the same VPN server at the same time.
- The IPSec operating mode "Authentification Header" (AH) cannot be used.
- Since the VPN software does not recognize when the Internet connection is cleared, it will not automatically negotiate a new VPN connection to the VPN server when the Internet connection is re-established. This, however, is necessary as the FRITZ!Box normally obtains a new IP address from the Internet service provider when a new Internet connection is established.
Therefore, the FRITZ!Box should permanently maintain the Internet connection and not clear the connection when it is idle.