I have the GLi.Net MT6000 configured in AP mode, the upstream router has IPv6 disabled, I want a pure IPv4 LAN network, I have noticed in the Associated Station list, many devices with an IPv6 address starting with fe80:: , I think this might be related to local IPv6, do I have to disable in the LAN interface the Delegate IPv6 prefixes setting or is there another setting to disable this IPv6 local address assignment? Thanks
IPv6 is a protocol that does not need configuration therefor you can't disable it for all devices. If a device wants to use it, it will.
But: Your router can block IPv6 traffic by not providing the routing rules. So as long as you did not enable IPv6 on the router you are safe because the devices might only be able to talk to the local network.