Registro DMARC
v=DMARC1; p=reject; adkim=r; aspf=r; rua=mailto:dmarc_rua@emaildefense.proofpoint.com; ruf=mailto:dmarc_ruf@emaildefense.proofpoint.com;

Servidores DNS Principal (mname) y Secundario (rname)
host: springcontentmanagement.com
class: IN
ttl: 21600
type: SOA
mname: ns1.markmonitor.com
rname: hostmaster.markmonitor.com
serial: 2024121601
refresh: 86400
retry: 3600
expire: 2592000
minimum-ttl: 172800