Servidores DNS Principal (mname) y Secundario (rname)
host: phosagro.biz
class: IN
ttl: 3600
type: SOA
mname: ns1.phosagro.ru
rname: hostmaster.phosagro.ru
serial: 53
refresh: 1200
retry: 600
expire: 1209600
minimum-ttl: 3600