SOA Parameters

Very poorly understood
many operators simply copy-and-paste it
causing troubles in some cases

@ 1D IN SOA  <primary_server> <admin_mail_address> (
            2004111905      ; serial number
            3600            ; refresh interval
            600             ; retry interval
            2419200         ; expire
                            ; (4 weeks in this case)
            1200            ; "minimum" TTL
            )