[gentoo-user] Re: Sendmail confused by network change

[Ian Zimmerman]

On 2017-09-20 11:45, Bas Zoutendijk wrote:

> When I boot at home, Cron sends mail to root@××××××××.homedomain.
> ‘homedomain’ is automatically added to all host names on my home
> network by the router.  It can only be resolved inside the network; it
> is not a registered domain name.  I can receive mail from Cron just
> fine.
>
> When I boot at work, Cron sends mail to root@hostname.  Note that the
> domain name ‘workdomain’ is not added to the host name.  I can still
> receive Cron mail.  However, when I take the laptop home without
> rebooting and connect to the home network, Sendmail is unable to
> deliver the Cron mail for root@××××××××.homedomain and sends
> notifications of this to root@××××××××.homedomain, which somehow do
> seem to arrive without problems.  The error message is “config error:
> mail loops back to me”.

According to crontab(5), you can configure where the mail is sent, by
setting the MAILTO variable in the crontab file.  [This is for cronie, I
am not sure if other cron variants do this.]  So, you could tell it to
send to <me@localhost>; presumably this would solve the problem.

Despite being one of the retro/traditionalist guys on this list, I have
to say installing sendmail just for this purpose doesn't seem
proportionate.  Even if you don't want to look into the smallish MTA
packages (nullmailer etc.), you can make /usr/sbin/sendmail to be a
pretty trivial script (or a link to one) that just locks the destination
mailbox and appends the input to it.  Heck, procmail could do that.

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