How do a prevent misuse of the 3CX system when it is possible to login with just a possibly weak mailbox PIN ? In many cases port 5060 will have to be open to the internet (when using VoIP DIDs or VoIP termination). How wo prevent that weak mailbox PINs get exploited ? Can I somehow disable certain users from the ability to login just with the mailbox PIN ? There should be an option to allow login with PIN only over the tunnel functioality.