Registro DMARC
v=DMARC1; p=none; adkim=r; aspf=r;

Servidores DNS Principal (mname) y Secundario (rname)
host: tc-group.it
class: IN
ttl: 3600
type: SOA
mname: dns.technorail.com
rname: hostmaster.tc-group.it
serial: 1
refresh: 86400
retry: 7200
expire: 2592000
minimum-ttl: 3600

Servidor de Correo
host: tc-group.it
class: IN
ttl: 3600
type: MX
pri: 10
target: mx.tc-group.it

Información TXT
host: tc-group.it
class: IN
ttl: 3600
type: TXT
txt: v=spf1 include:trustmailer.com ~all
entries: Array