Steffen Nurpmeso via Postfix-users: > Wietse Venema via Postfix-users wrote in > <4vsq5f6q3nzj...@spike.porcupine.org>: > |Tim Coote via Postfix-users: > .. > |> SMTP headers are often 'folded' as they flow through MTAs. The > |> standard approach to folding and unfolding is covered in rfcs 5322 > ... > |3) Lines that exceed 998 bytes (not including <CR><LF>) cannot be > | sent in SMTP. The result of sending such text is UNDEFINED. > ... > | When a line is too long, the Postfix SMTP client inserts > | <CR><LF><SPACE> (controlled by smtp_line_length_limit). > > This is a deficit of the entire RFC *822 series that a superficial > whitespace is necessary at that point. It was simply not on the > table, and i got not even an answer on that in private > communication (but maybe because of my way of speaking things out, > i mean, isn't that just a desaster: this *breaks* the protocol). > (On the other hand the dinosaur nmh just got (partially) proper > line folding in September last year: > > > http://git.savannah.gnu.org/cgit/nmh.git/commit/?id=542cb12b6d0646b711772ee97c1e2aacf2bada86 > > and they will fail for the artificial case as i said in > > https://lists.nongnu.org/archive/html/nmh-workers/2023-08/msg00010.html > [https://lists.nongnu.org/archive/html/nmh-workers/2023-08/msg00011.html]) > > | Before Postfix inserted <CR><LF><SPACE>, some MTA would insert > | a line break after ~1024 without adding a space. This would > | "terminate" the message header, destroy the MIME structure, and > > This is really what they do? Then .. my "artificial whitespace" > thought of a decade ago would be wrong. I would have thought they > possibly reformat with RFC 2047 (if they can), as i said in the > msg00011 thing above.
Yes this was a real problem. For example, an email message like this: label: value label: value-that exceeds-smtp-limit ...zero or more label: value... MIME-Version-1.0 Content-type: multipart/mixed, boundary="foobar" END_OF_PRIMARY_HEADER This is a multi-part message in MIME format. --foobar first body part --foobar first body part --foobar-- Was received as: label: value label: value label: first-part-of-value-that-exceeds-smtp-limit END_OF_PRIMARY_HEADER first body line with remainder-of-value-that-exceeds-smtp-limit >From here on all remaining content including headers and MIME boundaries was received as one large non-MIME message body and was displayed to the user in its encoded form includeing MIME boundaries encoded text (quoted-printable or base62 encoded). Why did that happen? Because some MTA's input reader did not know if it was reading a header or body line. Wietse _______________________________________________ Postfix-users mailing list -- postfix-users@postfix.org To unsubscribe send an email to postfix-users-le...@postfix.org