Something

$1800
domain.net. IN     SOA      ns1.domain.net.     webmaster.domain.net. (
                0
                10800
                3600
                1800 )
domain.net. 1800   IN       NS ns1.domain.net.
domain.net. 1800   IN       NS ns2.domain.net.
domain.net. 3800   IN       A  0.0.0.0

# Automatic generated by my cron script, notice the 0 SOA, its only a test, but normaly whenever the 'client' app changes something, the time() gets put there ;)