E-mails servers seek for a MX records in order to identify the FQDN or IP address of a mail server. If there no MX records is found, the SMTP servers will consider the root A ADDRESS for that domain as the e-mail server and will attempt (and retry a couple of times) to connect to its mail ports to deliver e-mail as described in RFC5321.
This generates unwanted and unnecessary traffic for both endpoints. The standard way to avoid is described at RFC7505 in a very simple way: if a MX record with the value “.” (dot) is found, the SMTP will hard fail this delivery and will not attempt again for this domain because it clearly understands there is no e-mail server for this domain.
I’m trying to comply with RFC7505 for all my domains hosted at CloudFlare that does not have an e-mail sever but Cloudflare’s control panel gives me an error when I attempt to create a MX record with the dot value. The following error message appear:
“NS Validation Error (Code: 1004) Content for MX record must be a hostname.”
Could Cloudflare change its field validation algorithm to allow users to comply with RFC7505, please?