Registro DMARC
Your DNS configuration needs immediate attention see https://icann.org/namecollision

Registro IPv4
host: corp.com
class: IN
ttl: 3600
type: A
ip: 127.0.53.53

Servidores DNS Principal (mname) y Secundario (rname)
host: corp.com
class: IN
ttl: 3600
type: SOA
mname: ns1-38.azure-dns.com
rname: azuredns-hostmaster.microsoft.com
serial: 1
refresh: 3600
retry: 300
expire: 2419200
minimum-ttl: 300

Servidor de Correo
host: corp.com
class: IN
ttl: 3600
type: MX
pri: 10
target: your-dns-needs-immediate-attention.corp.com

Información TXT
host: corp.com
class: IN
ttl: 3600
type: TXT
txt: Your DNS configuration needs immediate attention see https://icann.org/namecollision
entries: Array

host: corp.com
class: IN
ttl: 3600
type: SRV
pri: 10
weight: 10
port: 0
target: your-dns-needs-immediate-attention.corp.com