From: Sergio Luiz Novaes (algol@LCC.UFMG.BR)
Date: Wed Aug 21 2002 - 09:44:32 EDT
Just my few cents. If you stop the daemon you only will sent email, not
receive, as Holger told us. But there is a little problem, think in the
case your receiver mailer is down or can't receive the email or something
else, your sent mail will go to the mqueue and will stay there forever. So
the delivery couldn't be immediate. Sent', or try to do it, queued emails,
not delivered for many reasons, is another sendmail daemon function.
If what you want is just sent mail on this machine, take care to
disable the sendmail daemon and add a crontab line to run sendmail to
process your queued messages (if something is there) at the 30m interval
(default for AIX). something like:
0,30 * * * * /usr/lib/sendmail -q
This process is very similar to put sendmail on inetd control, not
running as a daemon.
Regards,
Sergio Luiz Novaes
LCC/UFMG - CENAPAD-MG/CO
Tel: +55 31 3499 5391/4910
Fax: +55 31 3499 5390
Holger.VanKoll@SW
ISSCOM.COM To: aix-l@Princeton.EDU
Sent by: IBM AIX cc:
Discussion List Subject: Re: Sendmail
<aix-l@Princeton.
EDU>
21/08/2002 07:31
Please respond to
IBM AIX
Discussion List
> When I ran sendmail -bp it reported "There is 1 request in
> the mail queue"
> which is what I would have expected however shortly after
> that the email
> was delivered.
Yes, because...
> Can someone explain what the sendmail daemon process is for
> (just receiving
> mail?)
... this is correct. The sendmail daemon accepts mail with SMTP on port 25.
To send mail, the (called) sendmail binary contacts the corresponding
sendmail-daemon, for local mail the sendmail daemon on the local host, for
remote mail the daemon on the remote host.
So if you stop the daemon, local mail wont be delivered. (at least not from
remote hosts).
> and if I leave the sendmail daemon down can I always expect
> immediate delivery of emails send from the system?
Yes, but it depends how mail is send. Most programs call the local
sendmail-binary and leave everything up to it.
A program could be written in a way that it will work if sendmail is not
installed, but something else (qmail etc.). This programm wont rely on
having a sendmail binary to do the work and try to deliver it by SMTP
itself.
It would still work for remote mail if it cares about the MX (f.e. does an
nslookup -q=mx hostname).
It could however be written in a way to contact the local MTA for
delivering. Then, it wont work; not for local and not for remote mail.
A strings progname|grep sendmail should be enough to check this; or call
any programm and do an ls -lu /usr/sbin/sendmail.
The normal case is, however, to call the sendmail binary like mail does.
Regards,
Holger
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