On Sun March 13 2005 15:09, Tony Finch wrote:
OTOH, there _might_ be some existing MTA this would break, though I
can't think why...
It might confuse software that analyses Received: fields, causing it to
fail to find all of them. However there is plenty of software out there
which already interleaves other fields amongst Received: fields, so robust
code already has to cope with it.
Any software that attempts to analyze Received fields is the work
of a misguided author and is unlikely to be useful. RFC 1123 notes
that:
Received: lines are primarily intended for humans tracing
mail routes, primarily of diagnosis of faults. See also
the discussion under 5.3.7.
and
Received: fields of messages originating from other
environments may not conform exactly to RFC822.
However, the most important use of Received: lines is
for debugging mail faults, and this debugging can be
severely hampered by well-meaning gateways that try
to "fix" a Received: line.
Aside from the "other environments", there exist widely-deployed
agents that generate Received fields which do not conform to even
the very liberal syntax of RFC 2822. E.g:
Received: from mail pickup service by crm with Microsoft SMTPSVC;
Fri, 4 Mar 2005 16:55:49 -0800