* Rupert Gallagher: > Two well known companies in my country persist in making the mistake > of writing their mid with a non-public fqdn, violating the rfc. [...] > been so for the past three years, with me sending detailed, manually > Their answer is that everybody else accepts their invalid mid, and > their servers are enterprise ibm / microsoft shitware that they are > unwilling to fix.
RFC 2822 (https://tools.ietf.org/html/rfc2822#section-3.6.4) does not state that a "public fqdn" (or any FQDN) is required in the message ID. Formally, the id-right portion can be any dot-atom-text. Also, the Message-ID header itself is optional, although recommended. In other words, you are the stubborn one, and wrong to boot. ;-) -Ralph
