on my old pc(2 NIC), if I connect like this 'second NIC'---'POEswitch'---'camera', it works...I can connect web interface and do any other things. but on my laptop(1NIC, 1wifi), if I connect 'NIC'---'POEswitch'---'camera', not work....I can only find camera in dahua configuration tool(from dahua wiki), cannot do all other things..include web interface(configuration tool's IP change is not work too). if I do ping to camera's ip(dahua default 192.168.1.108) on cmd, it indicates 'general failure'. camera is dahua 5231R-ZE but amcrest IP2M-851E is same...I think it is not related with camera's problem. Of course, I'm tried this 1) camera hardware reset 2) make exist them in same subnet(camera is 192.168.1.108 and computer adapter ipv4 setting is 192.168.1.10, subnet mask is 255.255.255.0) 3) disable anti virus 4) new PC(1 NIC) is same with laptop. absolutely, old PC works with same methode...I think it is related with firewall or hidden network setting.