I have set up two of these, terminated on a Draytek 2960 router. One is PPTP and the other is L2TP/IPSEC.
The PPTP one is especially simple to set up. I have set that up on various different Draytek boxes and all worked straight off. Draytek call them Teleworker VPNs.
Both of them connect i.e. authenticate, and I can see an IP has been allocated, which is from the LAN subnet of the router. From either, I can ping devices on the LAN.
I cannot ping e.g. cisco.com but ping shows the right IP so DNS is presumably working.
And I can run an RDP client but this goes to a fixed IP machine on the LAN, like the pings.
The client (phone, tablet, laptop) has no functioning internet access. A web browser, etc, does nothing... So it looks like the VPN termination cannot get outside the router.
It isn't the firewall; I can disable that.
Does anyone have any ideas? These sorts of issues are all over the internet but with no apparent solutions.
A supposedly identical setup, with identical clients, works fine on several 2955 routers, including one which served in the same place, before being replaced with the 2960. The 2960 is somehow different...