the variable NISDOMAIN in /etc/conf.d/domainname uncommented by default override DNSDOMAIN resulting in an unknown_domain of the system... and relative headcache to the poor user that (like me) does't understand why his computer refuse to take a domain name happened with baselayout-1.11.14-r8 in a fresh install with the livecd-2006.0
default NISDOMAIN value is "" which causes nothing to be run if NISDOMAIN is set to anything else, PEBKAC