I have a NIS master server (no slaves) with hosts.allow: ALL: LOCAL, .mydomainname.com and hosts.deny: ALL: ALL In this configuration, no clients will bind (reason, permission denied). However, when I comment out the "ALL: ALL" in the master server's hosts.deny, everything works. Others in my LUG have had the same problem, but only after upgrading from 5.2 to 6.0 or higher.
THe ypserv that comes with redhat 6.1 (and I presume 6.0 also) is compiled to use securenets rather than tcp_wrappers (do a /usr/sbin/ypserv --version to prove this for yourself). do a `man ypserv` to learn how the /var/yp/securenets file is set up. If you must use tcp_wrappers, then you'll need to recompile with the appropriate options.
not a real bug, the network configuration needs to be updated.