Configuring NIS on RedHat

[Alec Smith <alec shadowforum net>]

I've got assorted RedHat 6.x and 7.x machines configured as NIS clients
and a RH7.1 machine configured as a NIS server. How can I go about
limiting logins on several machines (file servers) such that only I
(user=alec) can login while other users' account info is available but
logins are not permitted?

I'd tried something like

+alec::::::
+:*:::::/etc/NoShell

in /etc/passwd (where /etc/NoShell is a text file explaining why access is
denied), but have had no success.

Thanks,
Alec