[HN Gopher] Who Reads Your Email?
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       Who Reads Your Email?
        
       Author : binaryanomaly
       Score  : 39 points
       Date   : 2023-03-10 11:30 UTC (11 hours ago)
        
 (HTM) web link (www.netmeister.org)
 (TXT) w3m dump (www.netmeister.org)
        
       | voytec wrote:
       | I run my own MTA for some 23+ years now. Google (supposedly)
       | reads only my emails sent by their users and same can be said
       | about other similar services.
       | 
       | > The Simple Mail Transfer Protocol (SMTP) relies on MX records
       | in the DNS to identify which server(s) it should hand the mail
       | off to.
       | 
       | Not necessarily (this statement is corrected later in the post).
       | One of my domains have no MX records and I use it for email
       | extensively. As per RFC2821, SMTP falls back to A (and AAAA which
       | have not existed back then) when the FQDN does not have
       | corresponding MX record [1]. I have only found it to be an issue
       | with one web service which utilizes hunter.io, which marks my
       | email address as invalid due to lack of an MX record. Real mail
       | services work perfectly fine. They (hunter.io) have the following
       | untruthful statement in their FAQ [2]:
       | 
       | >> We check if there are MX records on the domain. If there
       | aren't, the email address can't receive emails.
       | 
       | Linked post reflects lack of requirement for the MX record
       | correctly:
       | 
       | > As it turns out, no explicit MX record is indeed the most
       | widely found configuration: almost 119 million domains (58% of
       | all domains) are lacking any such resource record. Of those, 76
       | million (64%) do have an IP address and thus could at least
       | theoretically receive mail
       | 
       | [1] https://www.rfc-editor.org/rfc/rfc2821#section-3.6
       | 
       | [2] https://hunter.io/email-verifier
        
       | jeffbee wrote:
       | > everymailbox.com domain has 398 MX records
       | 
       | Ah yeah, these clowns. I distinctly recall, when rewriting the
       | DNS record cache used internally at Google (note: not the
       | resolver), thinking that surely no MX response would need more
       | than 8KiB, and finding these jokers.
        
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       (page generated 2023-03-10 23:00 UTC)