On 2022-05-13 at 02:59:41 UTC-0400 (Thu, 12 May 2022 23:59:41 -0700)
AC via Exim-users <agcme2002@???>
is rumored to have said:
> What configuration within exim defines how the outbound From header is
> formatted?
Hopefully, none. There's a long tradition of MTA (e.g. Exim, Postfix,
Sendmail) configurations being able to do literally anything, but
modifying headers is something they *should not do* in normal
circumstances, except *rarely* at initial submission. Generally
speaking, Exim has nothing to do with how From headers are structured.
> What I mean is whether the header has just an email:
> user@???
>
> vs. a name and email in brackets:
> A User <user@???>
Both are formally valid. Exim should not modify what the author of the
message and their MUA put in the From header unless you need to do
something like 'masquerading' a private domain. Even then, reformatting
(as contrasted with simply replacing components) is a bad idea.
> I'm asking because I have several machines that send nightly status
> messages where only a couple of the machines send with the second
> format (specifically it sends out: root <root@host>) while the others
> simply send out root@host.
Yes, different systems using different tools to send mail format From
headers differently. This is a function of how the mail is composed.
> All but one machine is configured to use a smarthost. Of those
> satellite machines, all but one sends out using the name/email format
> and uses only my domain (full format is "root <root@domain>). The one
> satellite machine simply sends out "root@domain" without a name. The
> smarthost itself also sends out its own messages but it uses
> root@??? with no name.
>
> The same programs run on all the machines (file system checks,
> antivirus, etc.) so they would all be using the same outgoing message
> format. I've tried to compare the exim configurations of the
> satellite hosts and they all seem to be using the same settings. The
> /etc/passwd files all look the same for the root account.
Look at how the mail is being composed. If the passwd entries for 'root'
have different Comment ("real name" or for oldsters like me, "GECOS")
field, the From headers will differ, if a traditional 'mail' or
'sendmail' implementation is used to construct mail. However, it is
possible that you've got programs doing their own SMTP-like initial
submission or manually contructing a full message and feeding it to
whatever happens to be at /usr/{bin,lib,sbin}/sendmail for
direct-to-queue submission.
> It's not affecting mail delivery
Right. Because headers don't govern delivery in an MTA.
> but it's just odd that the machines are somehow slightly different and
> I'd like to understand it better (and partially because it bothers me
> to see a list of emails that have slightly different From headers but
> that's just an OCD thing).
Different OSs and distros may use 'mailrc' and 'mailer.conf' files in
/etc/mail/ and/or ~/ to modify what specific tools are used and how they
behave. If your issues are with mail generated by 'cron' jobs, you may
have environment settings in the relevant crontab that effect how mail
is composed.
--
Bill Cole
bill@??? or billcole@???
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire
