Unit is 2860nplus. LAN P1 is connected to the main network switch and the phone system admin unit is connected to LAN P2. I can forward WAN ports to LAN IP addresses connected to P1 but cannot remotely access Phone system Admin page by forwarding the port to the Phone System IP address. The Phone system can be accessed from inside the LAN. I suspect if the cable on Port 2 was moved to the main switch the WAN forwarding would work. But why not through P2? I tried enabling VLAN0 and grouping P1 & P2 together but still didn't work. Unfortunately I am connected to the network remotely which is some distance away so cannot physically move cable at the moment. What do I need to do to get WAN port forwarding to LAN P2?

Try telnet connection to Draytek and see if you can ping the phone system internal IP. Check the Draytek is learning the phone system MAC address.

Presumably everything internal is on one subnet? Is the phone system in some clustered / HA configuration?

Thanks for the reply. Turns out the phone system itself was rejecting the forward even although port was correct and it worked with previous router. I gave the phone sys support company internal LAN access via RDP and they fixed it although I don't actually know what they changed in the Phone Sys management interface.