[comp.mail.misc] SCO TCP/IP and E-Mail Problems

david@twg.com (David S. Herron) (11/27/90)

[Cross-posted & followups-to comp.mail.misc since this isn't TCP/IP specific]

In article <9011190759.aa12077@ssmct62.ssc.af.mil> hutch@ssmct62.ssc.af.mil ("Capt E. Lee Hutchins") writes:
>	MMDF is the supported mail system for SCO UNIX.  MMDF does not come 
>with an ideal set of documentation.  (At least I
>can't make heads or tails out of it).  If any one has some ideas on Docs for 
>this system which are NOT in troff form I'd appreciate them.  Configuring MMDF
>without real documentation is a real *&^%$!

Yes, I agree .. that would be rather hard.

Docs for MMDF IIb update 43 (as well as sources) are available via
anonymous ftp from louie.udel.edu.  Both uunet.uu.net & gatekeeper.dec.com
keep the sources available.  I don't remember path names, but it was pretty
obvious ..

There's two mailing lists you should be interested in:

eurmmdf@zweibrucken-emh1.army.mil

	is Army people (I suppose that since they let me be on the
	list, they'll let Air Force people be on it ;-)) working with
	MMDF.  Though the discussion seems to be more generic Unix
	problems than MMDF problems ..

	eurmmdf-request@zweibrucken-emh1.army.mil, of course, for administrivia

mmdf2@relay.cs.net

	The "official" mailing list for MMDF support.  It manages to
	focus on MMDF pretty well.

	mmdf2-request@relay.cs.net, of course, for administrivia

>	I can recieve mail from other UNIX platforms, but we have another 
>mail system running which is based on 10NET, called "COURIER MAIL".  It has 
>an "SMTP" gateway working and other UNIX boxes (AT&T 3B2 600G's) can 
>receive and send mail fine.  My box on the other hand, does
>not work with it.  The mail ends up in a queue on the "COURIER SERVER" and is 
>never returned to me or the originator.  Anybody ever experienced this????  

This sounds like the "no background deliver" as described below ..

>	By the way my machine does not always accept:
>
>	telnet machinename.domain 25
>
>When tried manually from other hosts it often closes the connection before it
>askes for the identification.  

The MMDF SMTP server can be configured to do this if the IP address
does not have a known IP->host_name mapping.  Usually, though, it's
configured to give the "foo, you are a charlatan" message ..

>In fact it seems the more mail sent to my 
>machine, the less I actually receive.  I am on *several* mailing lists and I
>expected my mail volume to be much higher than it is.

This sounds like the SCO fumble where they made some bad suggestions
in their manuals.  Specifically -- that channels be configured for
"immediate" delivery & that no deliver daemon be run to handle
background delivery.  Theoretically it sounds nice .. if it gets
delivered immediately then it doesn't make sense to have a deliver
running since it will "never" see any mail.  But in practice -- if
lots of mail arrives at once -- then some of the messages will drop
into a queue and then never get delivered.

This is especially noticeable with the local channel.  If the
mailbox is locked (for instance, it's being delivered to by another
local channel process) the channel will exit with a "temporary
failure" status & the deliver controlling that channel will go
away.  The assumption was that a background channel would take up
the slack.  Rather than simply wait around for a little while --
you don't know how long this "temporary" condition will exist --
exiting works given a background deliver.

But SCO recommended *against* using a background deliver.  Fortunately
they've seen the error of their ways and currently suggest using
"mod=reg", which pushes all delivery through the background deliver,
and run

	deliver -b -clocal &
or	deliver -b -clocal,list,uucp,smtp &

In update 43 you can abbreviate that to

	deliver -b -c &

and that daemon will work with *all* channels in the system.

>	Finally, one other tidbit, I am running the latest version of "ELM" as
>my front end to mail.

This shouldn't make any difference -- unless ELM keeps the mailbox locked
all the time.

-- 
<- David Herron, an MMDF & WIN/MHS guy, <david@twg.com>
<- Formerly: David Herron -- NonResident E-Mail Hack <david@ms.uky.edu>
<-
<- Use the force Wes!

fitz@wang.com (Tom Fitzgerald) (12/04/90)

david@twg.com (David S. Herron) writes:
> But SCO recommended *against* using a background deliver.  Fortunately
> they've seen the error of their ways and currently suggest using
> "mod=reg", which pushes all delivery through the background deliver,

Why do you want mod=reg here?  It seems like, with mod=imm and a background
demon running, you'll get immediate delivery if the channel's idle, and
delayed delivery only if the channel's busy.  The only flaw should be that
messages arrive out-of-sequence.

By the way, people should be aware that the MMDF released with SCO has some
other real problems - it bounces mail that has perfectly valid destination
addresses but a bad return address; it rewrites addresses improperly
when bouncing mail, and often sends it to the wrong place; and it sends out
a copy of a message for each recipient, even at times when it could send
a single copy to multiple recipients.  Rumor has it that much newer versions
of MMDF exist, and are far better.

---
Tom Fitzgerald   Wang Labs        fitz@wang.com
1-508-967-5278   Lowell MA, USA   ...!uunet!wang!fitz