Subject: Re: Mail list envelope sender address
To: None <current-users@NetBSD.ORG>
From: D. J. Bernstein <>
List: current-users
Date: 11/25/1996 18:55:59
> I do know of sites where if every mailing list coming in were
> running on a qmail server, the load server would have a distinct
> possiblity of being brought to its knees.

Mm-hm. And I know a Tibetan monk who's going to destroy the world in
2001 if there are any sites left running sendmail.

Can we skip the paranoid fantasies, please?

Here's a dose of reality: A growing problem for big sites such as AOL is
all the sendmail hosts that say, ``Gee, I'd better stay connected to AOL
for a while in case I get more mail for them.'' What do you think that
does to AOL's virtual memory use?

Here's another dose: One of the nastiest problems in bringing AOL back
up after its outage was all the sendmail hosts that said, ``Hey, it's
up! I'd better flood it with all my waiting mail right now!''

> a piece of e-mail delivered anywhere from a tenth of a second to
> a few seconds earlier.

_Hours_. Not very common, but it does happen. These are _measured_
results for England several months ago and for Taiwan recently.

Occasionally sendmail's strategy means that mail doesn't get through at
all. It starts working its way down a long list of recipients, and the
connection dies. It tries again, and the connection dies again. The
connection sometimes stays up long enough to get the mail through to
one recipient, but it never stays up long enough for twenty recipients,
and sendmail is forced to bounce the message after several days.

Sick of sendmail? Don't get mad; get qmail.