@CatCat Which ISP has this requirement? Most routers will negotiate the speed&duplex.

@Frankfurts If you use DHCP to obtain an IP from router automatically, do those devices work normally? Those working devices have static IPs or dynamic IPs? After configuring static IP, you can try...

@Jackace Hey, Do the computers in your LAN network obtain IPv4 or IPv6 addresses? If they get IPv4 addresses, SPI firewall is enabled by default, no need to configure anything. But I guess you may...

@TheFatGuy For LAN-to-LAN, why not configure IPSec VPN? That will have less compatible issue, and more secure.

@yeng Voucher authentication has to keep running the controller, otherwise it will no longer provide authentication. See this article: https://www.tp-link.com/en/support/faq/1041/

@Lardo5150 I think they removed this feature as it is not important and accurate.