We've installed a Sonicwall TZ Firewall and have configured an L2TP/Ipsec VPN.
The SonicWall is connected to an internal router on the subnet 192.168.168.0/30 with the SonicWall on 192.168.168.1 and the internal router (a Dreytek Vigor) on 192.168.168.2
VPN clients are allocated to an L2TP range 10.10.20.10 - 10.10.20.49
Finally there is an internal subnet 192.168.100.0/24 on the Dreytek with a DNS and DHCP server on 192.168.100.63.
I'm having a lot of trouble getting VPN clients to access the 192.168.100.0/24 subnet. I've setup a static route on the SonicWall with the gateway 192.168.168.2. I've also setup a static route on the Dreytek pointing the VPN subnet 10.10.20.0/24 back to the 192.168.168.1 gateway.
I can successfully ping VPN clients (e.g. 10.10.20.11) and access shared networks resources on VPN clients from within the internal subnet but for the life of me I cannot access anything on the 192.168.100.0 range from a VPN client.
I'm not sure if there is something I missing in regards to routing or if I need to open up permissions on the routers? I've tried adding static routes on the VPN clients themselves and this hasn't done anything. I've also setup what I think is the correct access rule on the SonicWall (Allow, VPN -> LAN, any source -> 192.168.100.0) but still nothing.
Any ideas what I'm missing?