RFC 3030 which provides for the BDAT command and BINARYMIME which treats the message not as text at all and so I wouldn't expect that that text limit would apply, though the RFC doesn't discuss any limits.
In general, I don't see much utility in limiting the length of lines in the body of messages in the modern age. Headers and command/responses, sure. I assume people implemented to the Postel idea, and maybe even corrected messages when forwarding... but such corrections break dkim signatures now, which caused us to reevaluate message "corrections" when comparing the options of "being rejected/marked as spam" vs "rejected for message formatting violations". I think this is a general problem with text based protocols, people think they're easy and can be done by hand, and then things get complicated but you still deal with people doing /bin/sendmail foo < file or whatever without actually using libraries to properly compose messages... and so that works until it doesn't. It turns out people just want to get their mail, they don't want to be proper email/smtp formating pedantics. Brandon On Fri, May 17, 2024 at 12:01 AM Cyril - ImprovMX via mailop < mailop@mailop.org> wrote: > Hi everyone! > > I've got an email from one of my user telling me our server refused an > email because of a line too long. > The issue is referenced in the RFC at > https://datatracker.ietf.org/doc/html/rfc5321#section-4.5.3.1.6 and we > follow and respect that recommandation. > > I would not have raised this question here except that the user recently > moved from Cloudflare to us, and they shared with us a past email sent by > Sendgrid, that went through Cloudflare, and landed in their gmail inbox > successfully, **despite having a line of 1201 characters. > > So, I wonder, is there another RFC that specifies a bigger line length, or > are the RFC here just for decoration? > > Thank you for your help! > > Best regards, > Cyril - ImprovMX <https://improvmx.com> > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop >
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