On 2024-01-15 at 16:03 -0800, Randolf Richardson, Postmaster wrote: > > I have seen my share of MUAs that behave in weird ways when > > encountering things larger than it can handle, so you have > > to always cope for them in the mail server. Implementing different > > types of restrictions, and filtering things out of subjects and > > certain headers to evade crashing MUAs. > > 998 characters (not including CRLF), as I recall, is the > maximum > limit, which is specified in RFC 5322 (section 2.1.1): > > RFC 5322 :: Internet Message Format > > https://datatracker.ietf.org/doc/html/rfc5322#section-2.1.1
That's the limit for the *physical* line. The Subject: header could span multiple lines and thus be larger. Not that a Subject so large would make sense. I doubt your client would be able to show it to the user. Processing the email as if the subject was made of just the first 255 characters seems acceptable to me. OTOH, I have seen people writing long emails, all in the Subject: line, with hundreds of bytes. Yes, some people advocate for subject-only emails, but it didn't seem done on purpose. https://www.lifewire.com/what-is-eom-end-of-message-1171156 It didn't make sense. The user somehow confused the field where they should write... _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
