When you do a kickstart install and have a
auth --nisdomain DOMAIN --nisserver x.x.x.x
the NISDOMAIN entry in /etc/sysconfig/network
isn't written. /etc/yp.conf seems to be ok
hmmm ... it worked for me with the following line in my ks file:
auth --enablenis --nisdomain baz.foobar.com --nisserver 220.127.116.11 --useshadow
does that work in your case...?