@              IN  SOA      ns1.example.com. hostmaster.example.com. (
                              #{serial} ;serial
                              900 ;refresh
                              600 ;retry
                              604800 ;expire
                              86400 ;minimum
                             )
                  IN  NS       ns1.example.com.
;server host definitions
1                IN  PTR     ns1.example.com.
2                IN  PTR     www.example.com.