Aug 03 2016 02:44 AM
Hello
Are tere any news if (and when) Exchange Online plans to support RFC 7505 ?
RFC 7505 allows to define explicit null-mx record.
Gmail is already supporting this.
When I email a domain with null-mx record I instantly get this nice looking NDR:
Delivery to the following recipient failed permanently: user@domain.com Technical details of permanent failure: DNS Error: 33796847 DNS type 'mx' lookup of domain.com responded with code NOERROR The domain domain.com doesn't receive email according to the administrator: returned Null MX https://www.rfc-editor.org/info/rfc7505
Email sent from Exchange Online will go into 'normal' pending/retry mode and after 48H generate standard "host unreachable" NDR.
Aug 03 2016 03:08 AM