Servidores DNS Principal (mname) y Secundario (rname)
host: 1-3-5.com
class: IN
ttl: 86400
type: SOA
mname: ns1018.ui-dns.biz
rname: hostmaster.1und1.com
serial: 2017060128
refresh: 28800
retry: 7200
expire: 604800
minimum-ttl: 600