Servidores DNS Principal (mname) y Secundario (rname)
host: host4g.com
class: IN
ttl: 2560
type: SOA
mname: ns.host4g.com
rname: hostmaster.host4g.com
serial: 1777491793
refresh: 16384
retry: 2048
expire: 1048576
minimum-ttl: 2560

Servidor de Correo
host: host4g.com
class: IN
ttl: 900
type: MX
pri: 0
target: a.mx.host4g.com