As I said, AP is a Layer Two device. Only router which is Layer Three device, has ALG function.

Define "not connect very well". Try to set 750RE as static IP, see if the issue still exist.

AP is a Layer Two device. Only router which is Layer Three device, has ALG function.

The configuration above is OK.

tencun wrote Let's check the difference of topology: I have another Universal Repeater from a different vendor (AVM Fritz 300E) connected to my AP/Router (AVM Fritz.box 7270). [*]The 830RE acts as...

Seems that many other brands don't support WDS repeater. My Netgear router doesn't.