Servidores DNS Principal (mname) y Secundario (rname)
host: blackholes.five-ten-sg.com
class: IN
ttl: 21600
type: SOA
mname: ns.five-ten-sg.com
rname: postmaster.localhost
serial: 2012042601
refresh: 14400
retry: 3600
expire: 864000
minimum-ttl: 3600