homeoftheben,
I did not find a solution. I have found a workaround.
The 3216 must use the same software as the units with the built in
POE switch, there is no place in the software to turn off the DHCP, other than in
the network settings, one would think that if DHCP was selected here, it would work as a DHCP client getting a address automatically for the NVR. With this option selected, or deselected, I found it kept handing out addresses in the 192.168.0.0 network. The company I bought from, could not assist. I am reluctant to flash the software (NVR) unless someone can verify a new version specifically fixes this problem.
Dahua does not support their product well, this is where you get what you pay for.
My work around:
Segment the NVR/CAMERA Network on my home LAN. I did this with two Linksys WRT54G routers running DD-WRT, connecting my CCTV lan segment to the LAN connection on one router, and then connecting the WAN connection to my non-CCTV lan. I turned off the wireless/dhcp on the CCTV router and put some static routes in and configured the port forwarding on both routers. Remote access with iDMSS works fine. Doing this keeps the hosts which request a DHCP address on my non-CCTV lan.
All cameras and my NVR on my CCTV LAN are static IP's. So the NVR gets no requests to hand out IP's.