We have registered one domain called example.com with A and MX record with our public ip and email address format is email@example.com.
But Now we would like to register another domain called "testmail.example.com" and email id format will be firstname.lastname@example.org.
So is there any option in zimbra where this child domain can use parent domain's IP to for mail communication ??
Can we do this on DNS level ??
OR we need to register testmail.example.com domain seperatly with A nad MX record ??