I'm going to do my best to explain this - I hope it works!!

I have a Vigor 3900 that has VPN services running and users can login fine.

The 3900 lan settings are to relay DHCP requests to an internal DHCP server. Clients connected via the VPN are not receiving the DNS configs they should be getting from the DHCP server, even though LAN clients get it fine. In Windows I can work around this by configuring the vpn adapter within the client operating systems and they then work fine. However that work around is not possible with the iPhone software. Is there a way for me to configure something in the 3900 that will pass DNS settings to the clients connecting to it, even when it is not the DHCP server?

Thanks in advance and I hope this makes sense!