Hello,
If I have an export like:
/usr/temp -rw=ram:alligator
means that /usr/temp has "rw" permissions to ram and alligator machines and has "ro" to everyone else?
Yes. Of course, the normal permission modes still apply. If a file is only user writable (perms 6xx), then it still retains the same permissions on the system where it is remotely mounted, and only the user will be able towrite to that file.
Root loses all rights on NFS mounted filesystems unless the filesystem is explicitly exported giving root its normal privileges. Check the man page of share for more details.