Registro DMARC
v=spf1 include:spf.protection.outlook.com -all

Servidores DNS Principal (mname) y Secundario (rname)
host: outbound.protection.outlook.com
class: IN
ttl: 300
type: SOA
mname: ns1-36.azure-dns.com
rname: hostmaster.o365filtering.com
serial: 2021562360
refresh: 300
retry: 900
expire: 1209600
minimum-ttl: 60