Standard Resource Record Format
{name} {ttl} addr-class Record Type Record Specific data
Column 1 is the name of the domain record, or the “owner”.
Column 2 is the optional time to live field.
Column 3 is the address class; IN indicates the Internet class.
Column 4 is the type of resource record (A, MX, SOA, NS, CNAME, etc...)
Column 5 (and beyond) are the data fields. The types of data in these fields depend on the RR type.