Defines global parameters for a DNS zone—meaning a portion of the namespace on the Internet under a single administrative control—as defined in RFC 1035. Only one SOA record is permitted in a zone file. Considered to be not only the most critical but also the most complex record in the zone file, the SOA contains the root name of the zone, the TTL values, the class of record, and the primary or Master Domain Name Server for the zone. Zytrax, Inc. Start of Authority Record (SOA). [Online, November 17, 2004.] Zytrax, Inc. Website. http://www.zytrax.com/books/dns/ch8/soa.html.