I've been grappling with this question... trying to comprehend how you're implementing the logon/login. My first thought... can't you tell from the logon/login script what you're logging on/in to?How do you setup the GINA? MSGINA or NWGINA? Do users login or attach to NetWare? What if they logon/login to both?
I suppose you should be able to do an If Exist() on a NetWare and NT share to determine connectivity. One needs to be careful, because the OS may restore a connection, so you wouldn't be able to tell if you logged in or attached.
What about drive mappings. Would they not be specific to where you logon/login?
Then there's the search mappings that NetWare does. They would only exist if logged in to NetWare. Call a utility from that search path, and if it returns "not found" you're not logged in.