Hi guys! I think I get a solution. I find that online detection works in Auto mode by default. In this mode, the router determines the status of the line by PINGing the gateway of its WAN interface...

Hi Mike, As I know, this router will translate the source port of an outgoing packet for some safety consideration. And this behavior can't be changed. Also, symmetric NAT is built on this router...

It is recommand to support both A and B as a PD,and a PSE should support only one of them. So the problem is the camera isn't following the standard.