I'm happy with the case as specified. A few small things though: I think a mapping of guest to the Solaris nobody account would be a useful default configuration, it would then match what NFS does with unknown users - which is the closest NFS equivalent to CIFS guest access.
The property name of "guestok" feels clunky to me I'd have expected just "guest" but given NFS already has "aclok,nosub,nosuid" it seems to fit that model. -- Darren J Moffat
