On Sat, 29 May 1999 13:37:29 -0400 (EDT), Sam wrote:
The point I was trying to make is that when MTA are misconfigured, the
more traffic generation points (bounce, delay notification, etc) there
are, then more garbage will be sent and the more difficult it becomes
to use E-mail for communication.
>This is not an RFC-compliant DSN, unless you did not include all the
No it's not. Format wrong, and sent to From: address, not envelope
sender. If one does DSN, of course one should do it right.
>That does bring up an interesting point. An RFC-compliant DSN will go to
>the envelope sender address, and I'm not sure if ezmlm is smart enough to
>identify delayed DSNs. If it doesn't, it'll look like a bounce to it, and
>eventually it will kick you off the list. I'm sure that many will
>disagree, but in this case I believe that this would be an ezmlm bug.
ezmlm-weed filters out DSN. Of course, who can keep up with all the
home brew by major software vendors ;-)
Speaking of ezmlm: I used to assume that on a ezmlm list, one would see
less that 5% bounces. I have now looked at a few large lists, and the
number of bouncing addresses at any time on a busy list is about 10%.
ezmlm removes the legitimate problem addresses. remaining are bounces
for "over quota", "we do not relay" (we _are_ an MX for the host, but
our sysadmin installed the new sendmail without knowing what /she was
doing), "sender domain must resolve" (people do a lot of DNS lookups
for spam checks, but aren't well connected to DNS - some even make this
a permanent error), looping message (>15 received headers), etc, and my
all time favorite "syntax error in Reply-to: header" (yes, they check
each header and seem to do one DNS lookup per address in the message).
Thus, the majority of "bounces" are intermittent failures due to
configuration errors and spam control, and of course DSN adds to this.
Conclusion: In an attempt to make it better and safer it has been made
too complicated for at least 10% of sysadmins. Any new "feature", such
as DSN should be viewed against this.
-Sincerely, Fred
(Frederik Lindberg, Infectious Diseases, WashU, St. Louis, MO, USA)
