Re: Max length of an email subject line -- PCTECH

Hi Bob -

Anybody know what the maximum length of an email's subject line can be?


The subject is an unstructured field so it has no maximum length.

There is a maximum line length of 998 (excluding the trailing CR and LF)however the subject can be folded across multiple lines so that is not arestriction on the length of the subject itself.


From rfc2822 about unstructured header fields:

   Some field bodies in this standard are defined simply as
   "unstructured" (which is specified below as any US-ASCII characters,
   except for CR and LF) with no further restrictions.  These are
   referred to as unstructured field bodies.  Semantically, unstructured
   field bodies are simply to be treated as a single line of characters
   with no further processing (except for header "folding" and
   "unfolding" as described in section 2.2.3).

See http://www.rfc-editor.org/rfc/rfc2822.txt about email messages
and http://www.rfc-editor.org/rfc/rfc2821.txt about SMTP.

Ken
http://www.kensims.net/
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