Servidores DNS Principal (mname) y Secundario (rname)
host: ebooks.im
class: IN
ttl: 21600
type: SOA
mname: pebbles.iom.com
rname: dnsadmin.advsys.co.uk
serial: 1788118201
refresh: 16384
retry: 2048
expire: 1048576
minimum-ttl: 2560