You're right, there is only one Ethernt port, and that will be WAN port when it's on Rotuer mode, so cannot connect to a client device by cable. You can use TL-WR810N, it has two Ethernet ports.

Hi, you can use Bandwidth Control only when it's on Wireless Router mode. When it's working as an Range Extender, the bandwidth control should be setup on the main router....

:D good sharing

You tried factory reset the cam? Also you can configure it through web interface. https://www.tp-link.com/en/faq-820.html Or update firmware https://www.tp-link.com/en/faq-1972.html

What's your SNR and attenuation downstream value? Did you talk to your ISP about this line issue? What's the current rate showing on the VR600 DSL status page?

What's the model number of your device? And hardware/firmware version? Do you mean that if the client PC connects to the tplink Wi-Fi, you can connect to VPN; but not via wired connection to router?