Martin G. Diehl wrote:
I have a question about the Message-ID, References, and
In-Reply-To: headers. Although this may not directly
relate to SPF [...]
Indeed, this is mostly off-topic.
These headers would be valid as part of one reply,
In-Reply-To:
<a06110403be36e65087ef(_at_)[209(_dot_)86(_dot_)7(_dot_)86]>
References: <a06110403be36e65087ef(_at_)[209(_dot_)86(_dot_)7(_dot_)86]>
These headers would also be valid as part of another reply,
In-Reply-To:
<42117B3E(_dot_)3070106(_at_)sitka(_dot_)engin(_dot_)umich(_dot_)edu>
References: <a06110403be36e65087ef(_at_)209(_dot_)86(_dot_)7(_dot_)86>
<42117B3E(_dot_)3070106(_at_)sitka(_dot_)engin(_dot_)umich(_dot_)edu>
[...]
Am I correct in thinking that if the original message-id had
square brackets in the id-right, those characters have to be
included in every reply?
Yes, because "[209.86.7.86]" and "209.86.7.86" are two entirely different
things in the context of e-mail hostnames. "[209.86.7.86]" is an IP
address literal, while "209.86.7.86" is a (non-existent) domain.