Is there any chance that when a client shows a master console but in red (not connecting), it could give a bit more information about why it is in red?
For example, today in teaching a client wouldn't connect because the console did not have multi-console enabled on port 2. It look me a while to check this because I'd assumed that in this case the console wouldn't show up in the client at all, rather than showing up in red.
Or similarly, when it won't connect because of mis-matched software versions or library versions.
As others have noted there seem to be a range of issues occurring when trying to connect Mac clients running the current OS to consoles. Having the client report on 'common' issues would allow those to be eliiminated quickly before then messing around with the OS network settings.
Ta,
Rob.