Hello. I'm hopeful someone out there has encountered similar problems to my own and can point me in the right direction. I've spent the last three hours trawling the archives, and the last 90 minutes getting the 1.5.1 firmware update to stick without crashing the router.

We just upgraded our BT Business connection with a fixed IP to BT Infinity. They came out, installed their modem/router combo and the connection worked as expected, except....

There is evidently a known problem with upload speeds on the BT-supplied modems in that they are artifically capped at 2MB even though the local circuit is capable of much higher transfer rates. BT actually provide a credit towards the purchase of an alternate VDSL modem/router because of this limitation. Enter the Vigor 2750Vn.

The primary device that runs on this network is a Snow Leopard Server (Mac OS 10.6) that provides iCal calendar server services and mail servers for our company newsletters and subscriber lists. This all worked correctly (and still does) if I use the BT-supplied modem/router. I set up the server as the DMZ device and all requisite traffic for all the calendar, web and mail ports was handled without issues by the Snow Leopard Server. The network settings when the BT modem/router is connected and the server set to obtain its IP by DHCP show our fixed IP assigned to the Snow Leopard Server.

By contrast, the network settings when the Vigor router is connected, and the Snow Leopard Server set up as the DMZ device clearly show that the Snow Leopard Server has been allocated a private IP by the DHCP server in the Vigor router. This is causing major problems for the Snow Leopard Server as it requires fully functional DNS and reverse DNS on the IP/hostname assigned to the server. While the Web server running on port 80 is reachable from outside the subnet, the calendar server (port 8008) and the mail server (ports 25, 110 and 587) are not.

Somehow I need to emulate the network settings as they exist when using the BT-supplied hardware with the new Vigor router. Can anyone on these forums point me in the right direction please? I've been through all the FAQ documents but am unable to find anything that would help me to enable the correct settings.

Thanks in advance for any help you might be able to provide.

Additional to the original post, I've found references to a Draytek feature called True DMZ that seems to be what I need, but cannot find anywhere in the Web interface that this could be enabled. Does anyone have any ideas? I've also tried to find a listing of models that support this 'feature' but that doesn't seem to exist either.