search a.domain.com b.domain.com domain.com
nameserver x.x.x.x
nameserver y.y.y.y

nslookup server

ping server

ping server.a.domain.com

ssh server

# Mac OS X Notice
#
# This file is not used by the host name and address resolution
# or the DNS query routing mechanisms used by most processes on
# this Mac OS X system.

nameserver 10.0.100.2
domain  home.cainmanor.com

sudo killall -HUP mDNSResponder