A look inside a zone file /etc/bind/db.example.edu.au: example.edu.au. IN SOA bob.example.edu.au. root.example.edu.au. ( 2001060100 ;serial (version) 10800 ;refresh period (3 hours) 3600 ;retry interval (1 hour) 604800 ;expire time (7 days) 86400 ;minimum TTL (24 hours) ); example.edu.au. IN NS bob.example.edu.au. example.edu.au. IN NS fred.example.edu.au. example.edu.au. IN MX 100 alice.example.edu.au. bob.example.edu.au. IN A 192.168.142.1 fred.example.edu.au. IN A 192.168.142.2 alice.example.edu.au. IN A 192.168.142.4