During my experiments enabling/disabling WiFi re a different thread, I came across a potentially nasty issue. It affects the configuration where you have enabled more than one WiFi SSID, such as a 'guest WiFi' attached to a separate Interface Group. That is useful as it is the means by which you allow visitors to use your WiFi for web access, without having access to your internal network.
With such a configuration, if you disable and re-enable WiFi, or possibly (not confirmed) you even change any of the WiFi settings, you will find that the guest WiFi has disappeared from the isolated group you intended, and reappeared on the default group. ie, your 'guests' now have full access to your internal network
It can be fixed be redoing the Interface Group configuration. I see it's already been posted on Billion support forums, so not just me doing something daft.
PS: My affected firmware version is 2.32d.
