$ORIGIN ttlext.
@			IN SOA	ns hostmaster (
				1        ; serial
				3600
				1800
				1814400
				3
				)
			NS	ns
ns			A	10.53.0.1
a			TXT	"soa minttl 3"
b		2S	TXT	"explicit ttl 2"
c			TXT	"soa minttl 3"
$TTL 10M  ; bind9 extention ttl
d			TXT	"default ttl 600"
e		4	TXT	"explicit ttl 4"
f			TXT	"default ttl 600"