[Mailman-Users] Emails Not Being Delivered to All on List

[Brad Knowles]

At 4:56 PM -0600 10/31/06, Bruce E. Breeding wrote:

>  I went to the URL and read it.  Thank you (and thank you for the other
>  comments in your email).   However, the FAQ merely said that it (leaving the
>  verification turned on) will "slow delivery rates from mailman to your MTA
>  significantly".

Correct.

>  Can you elaborate?  (I'm looking for something substantive to convey to my
>  web service provider.)

As one of the authors of a lot of material in that FAQ entry, I will 
try to answer your questions.

>  Is the delay minutes?  hours?  "it depends [on ___ ]"?

Officially, it depends.  But turning on DNS verification of e-mail 
addresses can cause messages that could be delivered in just a few 
seconds to take minutes or hours or more.  Do this across your whole 
list, and you might be able to go from handling thousands (or tens of 
thousands) of users with DNS verification turned off, to having 
difficulty handling hundreds of users with DNS verification turned on.

DNS verification is very, very bad news for proper operation of 
mailing lists.  So is anti-spam or anti-virus scanning.  All that 
kind of stuff should be done *ONLY* on message input into the mailing 
list system, and *NEVER* on message output from the mailing list 
system.

>  Does the delivery eventually take place, or, do some recipients really never
>  get the emails?

Maybe.  Maybe not.  But your throughput could go down substantially, 
and it may be impossible to reliably deliver mail to certain users.

-- 
Brad Knowles, <brad at shub-internet.org>

Trend Micro has announced that they will cancel the stop.mail-abuse.org
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