coca koala wrote

I know this issue indeed...But I am not so familiar with TL-WDR4300.

Since you are using two subnet, I think you have a basic knowledge of routing, right?

1. As you can check, the TL-WDR4300's LAN interface has no gateway field. When you are using it as an AP, only the LAN port is functioning but it has no default gateway, which is why it won't response when you are accessing it from another IP segment (subnet).

This is factor #1. To overcome this factor, you can navigate to Advanced routing --> create a static route for your desired subnet. For example, destination 10.79.73.0/mask 255.255.255.0, and the gateway should be your upper router which is connection directly to the TL-WDR4300.

2. Then you must also navigate to Security menu to enable remote management for all segment or only for your described 10.79.73.0. If you don't enable remote management, the router still won't access any requests from remote IP segment.

3. The above two steps are necessary, but I am afraid (I am not sure) it is not sufficient. As I know most TP-LINK routers has updated with CSRF protection which will check the referer field in HTTP requests. As a result, only hosts with the same LAN subnet can access from LAN port, while remote hosts can only access from WAN port. If a remote host attempt to access the router from LAN port, the router will refuse by saying "You have no authority to access". -- If you do see this warning after finishing step1 and step2, the only way left is to downgrade the firmware to TL-WDR4300_V1_130319. If not, then congratulations! It works