Registro DMARC
v=DMARC1; p=reject; rua=mailto:dmarc_rua@emaildefense.proofpoint.com; ruf=mailto:dmarc_ruf@emaildefense.proofpoint.com; aspf=r; fo=1

Servidores DNS Principal (mname) y Secundario (rname)
host: sainsburystoyou.net
class: IN
ttl: 21600
type: SOA
mname: edns63.ultradns.com
rname: dns-admin.sainsburys.co.uk
serial: 2023042403
refresh: 86400
retry: 86400
expire: 86400
minimum-ttl: 0