Use the latest Mod firmware from
@cor35vet
I've mirrored a copy here:
Index of /DAHUA/MODFIRMWARE/EOS/
Either set your DNS to 1.0.0.1 or use your router to block it from talking to the Internet.
(Even with false DNS entries, it still calls home to it's hard coded IP addresses for easy4ip even when disabled....bug in the official Dahua firmware.
IVS should be fine, I have no issues with the one I have using 2 trips but I wouldn't push it too hard as a lot of CPU time is still being wasted on easy4ip.
Hopefully
@cor35vet will throw up another firmware soon that has the Dahua bug fixes.