VPN - PPTP Sever to use DHCP Relay

[Blarm1959]

I would like to use my office DHCP server to assign IP address and DNS setings to VPN clients.

I have set up the 7800DX IP address as 10.19.86.1 and configured it to use DHCP Relay on the LAN settings and that works for wireless connections from inside the office.
The office DHCP gives out addresses 10.19.86.200 to 10.19.86.229 and DNS 10.19.86.106, 10.19.86.1

For the PPTP VPN Server there is 'IP Address Assigned to Peer' start from: setting (10.19.86.230) and this does allocate the IP address to the VPN client.
I would like to use my office DHCP server to assign that (and DNS settings) instead.

After making a VPN connection on the client, if I do an ipconfig /all, for DNS it shows 2 DNS servers:
10.19.86.1
10.19.86.1
i.e. both the same (the 7800DX IP address)
How does the 7800DX assign these two identical DNS servers to the VPN client?

I can configure my VPN connection on the client to use 'Use the following DNS server addresses', but that means I will have to change everyone else's VPN connection params manually.

Is there any way to get the 7800DX to either use my office DHCP server for VPN clients or change the 2 DNS entries that the 7800DX is giving out?

Thanks

[billion_fan]

Under 'Configuration >> LAN' have you tried to untick 'Use Router's setting as DNS Server' and manually enter your DNS server, then check your VPN clients again?

[Blarm1959]

Under 'Configuration >> LAN' have you tried to untick 'Use Router's setting as DNS Server' and manually enter your DNS server

I have already done that and entered:
10.19.86.106
10.19.86.1

You can only enter those when
DHCP Server=Enabled

I have
DHCP Server=DHCP Server Relay
DHCP Server IP Address=10.19.86.106
and those entries are now not visible

The DHCP Server Relay works fine for wireless clients.
However VPN clients still seem to get their IP address from PPTP VPN Server 'IP Address Assigned to Peer' start from: setting (10.19.86.230).
The VPN clients DNS settings are always set to:
10.19.86.1
10.19.86.1
i.e both primary and secondary DNS are set to the 7800DX IP address (10.19.86.1)

[kmr1962]

Have you tried configuring the router WAN interface to use static DNS addresses
You can then point these to your office DHCP server.

The VPN client will still use 10.19.86.1 as its DNS but the router should then forward the requests to your office DHCP server

I have not tried this and it assumes that the router can use LAN addresses for the WAN DNS.