On 07/08/09 23:55, John W. Baxter wrote:
>
>
>
> On 7/31/09 2:29 AM, "Adam Funk"<a24061@???> wrote:
>
>> On 2009-07-30, Heiko Schlittermann wrote:
>>
>>> Adam Funk<a24061@???> (Do 30 Jul 2009 16:49:08 CEST):
>>> ...
>>>> curious about the second: can a message really get to the delivery
>>>> point without a Message-ID header?
>>>
>>> If I remember well, only in submission-mode exim should do some
>>> fixups (Message-ID, Date, Sender, ...).
>>
>> Yes, I remember setting that option a few years ago on my outgoing
>> exim. ISTR (but I could be wrong) that I needed to do it because
>> messages were getting rejected by subsequent mail servers for not
>> having MIDs.
>>
>
> [Catching up]
> Unfortunately, having a Message-Id: header is still a SHOULD, even in RFC
> 5322. So one really ought not to reject based (only) on their lack. It would
> be very nice if I could. (And if running a server only for myself, I likely
> would, with provision for an exception list.)
>
A SHOULD in the RFC, is about the same a MUST. That means, with SHOULD,
you are not "forced" to implement it, but if you don't, expect to have
problems.
3. SHOULD This word, or the adjective "RECOMMENDED", mean that there
may exist valid reasons in particular circumstances to ignore a
particular item, but the full implications must be understood and
carefully weighed before choosing a different course.
