$ORIGIN 1.16.172.in-addr.arpa.
$TTL 1D
@     IN SOA  dns-test1.emrlab.com. hostmaster.emrlab.com. (
              200405190  ; serial
              28800      ; refresh (8 hours)
              14400      ; retry (4 hours)
              2419200    ; expire (4 weeks)
              86400      ; minimum (1 day)
              )

              NS      dns-test1.emrlab.com.

1             PTR     serenity.emrlab.com.
2             PTR     workstation.emrlab.com.
3             PTR     media.emrlab.com.
4             PTR     pfsense.emrlab.com.