Registro DMARC
v=spf1 a:dns.u1holding.com ~all

Servidores DNS Principal (mname) y Secundario (rname)
host: u1holding.com
class: IN
ttl: 3600
type: SOA
mname: dns1.p06.nsone.net
rname: hostmaster.nsone.net
serial: 1954032896
refresh: 43200
retry: 7200
expire: 1209600
minimum-ttl: 3600

Servidor de Correo
host: u1holding.com
class: IN
ttl: 3600
type: MX
pri: 0
target: mx.u1holding.com

Información TXT
host: u1holding.com
class: IN
ttl: 3600
type: TXT
txt: v=spf1 a:dns.u1holding.com ~all
entries: Array