Registro DMARC
v=DMARC1; p=reject; rua=mailto:dmarc_rua@emaildefense.proofpoint.com,mailto:dmarc.reports.rua@citi.com

Servidores DNS Principal (mname) y Secundario (rname)
host: citibanamex.com.mx
class: IN
ttl: 3600
type: SOA
mname: ns1.nsroot1.com
rname: hostmaster.citi.com
serial: 2021094221
refresh: 3600
retry: 300
expire: 2419200
minimum-ttl: 3600