Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!emory!utkcs2!betelgeuse!moore
From: moore@betelgeuse.cs.utk.edu (Keith Moore)
Newsgroups: comp.mail.sendmail
Subject: Re: sendmail from inetd?
Summary: those who do not understand UNIX are destined to reinvent it, poorly
Message-ID: <1991Jan6.011903.5309@cs.utk.edu>
Date: 6 Jan 91 01:19:03 GMT
References: <8653@uwm.edu> <1991Jan03.092822.20859@turnkey.tcc.com>
Sender: news@cs.utk.edu (USENET News System)
Reply-To: moore@cs.utk.edu (Keith Moore)
Organization: CS Dept -- University of TN, Knoxville
Lines: 64

In article <1991Jan03.092822.20859@turnkey.tcc.com> jackv@turnkey.TCC.COM (Jack F. Vogel) writes:
>In article <8653@uwm.edu> jgreco@archimedes.math.uwm.edu (Joe Greco) writes:
>>I was wondering if anybody has tried the following:
>>
>>Can sendmail be run from inetd?  sendmail has the option to run SMTP on
>>stdin/out, and if  possible, I'd like to run it that way instead of "-bd".
> 
>>Sendmail: v5.65 (mx, no IDA).
>>System: IBM 6152 RT's running a modified AOS4.3 (very close to BSD)
> 
>Odd that you should ask this! sendmail on AIX has this capability and my
>question always was why someone would want to introduce this "feature":-}.
>The quick answer to your question is 'NO' you cannot do this without code
>change. 

That's rather odd.  Here's an excerpt from our local document on
adapting UNIX systems to the UTK environment:
------------------------------------------------------------------------------
[optional]  To avoid the overhead of always having sendmail running,
you can start sendmail from inetd and cron.  To do this:

1.  Create an executable shell script named /usr/etc/smtpd as
    follows:

#!/bin/sh
exec /usr/lib/sendmail -bs 1>&0 2>&0

2.  Add the following line to /etc/inetd.conf:

smtp stream tcp nowait root /usr/etc/smtpd

    (Syntax may be different for your system.  See man inetd for details)

3.  Add the following line to the crontab file:

15 * * * *      /usr/lib/sendmail -q

    (The exact syntax varies from system to system.)  This entry is required
    in case sendmail is not able to deliver messages immediately.  Normally
    the main sendmail process takes care of periodically retrying queued 
    messages; but since sendmail is not running all of the time now, we have 
    to do this explicitly from cron.  The above example runs the queue once
    per hour -- you might want to do it less often.

4.  Comment out the startup code for sendmail in /etc/rc.local (or whatever).

5.  If sendmail is running now, kill it.  Also send a HUP signal to inetd.

6.  Try it by telnet-ing to the local SMTP port and sending a piece of
    mail.
------------------------------------------------------------------------------
This works fine on 6150 RTs under 4.3, although we put the smtpd program in
/etc instead of /usr/etc.  It should work on any Berkeleyish system, modulo
differences in crontab and inetd syntax.

Of course it does have the overhead of firing up the shell and doing an extra 
exec, but the assumption is that you don't receive a message very often on 
your workstation. Our sendmail.cf file rewrites all outgoing mail to be
from user@cs.utk.edu, so replies go to the mail server rather than the
workstations.  For the occasional message that does get sent directly to
the workstation (ignoring MX records), the above hack works just fine.
Keith Moore / U.Tenn CS Dept / 107 Ayres Hall / Knoxville TN  37996-1301
Internet: moore@cs.utk.edu      BITNET: moore@utkvx
``Paranoia is a drug which is more dangerous than any controlled substance.''