Re: message-Id has localhost

[Ken Hornstein]

>> I mean, that's not a reason in my thinking?  Like, WHY do people want
>> that?
>
>To be able to uniquely refer to that email in future by knowing what the
>message-id field contains.  The reference may be to oneself or to other
>recipients.  That is the purpose of the field.  Not knowing the field's
>value lessens its worth to tracing the flow through downstream parties
>in log files.

I think we're probably not going to agree whether or not those reasons
qualify as "vague", but, fine.  That's not really my point; I honestly
don't care if people want to generate their own Message-IDs.  What I _do_
care about is when they do and then complain that nmh is using the
"wrong" hostname to do so; I do not believe there is solution to this
that will universally work, or even work in a large majority of cases
considering the configuration of the modern Internet.

To Mike's question:

>Can we just use "localname" from mts.conf?

We COULD, it would just be wrong for some people.

That's the "local" hostname, and is used for a bunch of things INCLUDING
constructing the default hostname for email addresses.  But here's a
thought experiment: let's say you set it to 'gmail.com' because your
email is hosted at gmail.  There's no way you could guarantee your
Message-ID isn't going to be used by gmail.com already.  Yes, you could
send your default email address via another mechanism, but a quick
glance at the code makes me realize that's still used for a bunch of
things.  We could add another knob, but honestly I'd rather people just
use 'random' if the existing logic doesn't work for you.

To Mike's other point:

>> FWIW, I took a quick look at the MTAs Postfix and Sendmail; Postfix does
>> not seem to have any Message-ID-specific configuration knobs, it hardcodes
>> adding a Message-ID based on it's idea of the local hostname.  Sendmail,
>> yes, it looks like you could change it if you really want to; it also
>> defaults to something based on the local hostname.  I am personally
>> skeptical that people actually configure this.
>
>gethostname() is not the same as what you said we were doing, which takes a
>trip through /etc/hosts.

Well, technically, it's constructing the Message-ID based on the value
of the 'j' Sendmail macro, which is used for a ton of things; that macro
value is configurable and in my limited sendmail experience you usually
do explicitly configure it (I do not know what that defaults to).

--Ken