Gateway to python-list is generating bounce messages.

Matt Nordhoff mnordhoff at
Sat Sep 13 00:15:05 CEST 2008

Steven D'Aprano wrote:
> On Thu, 11 Sep 2008 17:27:33 +0200, Sjoerd Mullender wrote:
>> When mail messages bounce, the MTA (Message Transfer Agent--the program
>> that handles mail) *should* send the bounce message to whatever is in
>> the Sender header, and only if that header does not exist, should it use
>> the From header.
> Who makes up these rules, and why should we pay the least bit of 
> attention to them?
> It's one thing to say "right or wrong, that's what list admins do and you 
> have to deal with their behaviour whatever way you can". It's another 
> thing altogether to take the legalistic attitude of "never mind the 
> consequences, the standard is the standard and must be unthinkingly 
> obeyed". If the standard does more harm than good, then ignoring the 
> standard is the right thing to do. (Better would be to change the 
> standard, but that probably won't happen until there's a critical mass of 
> people who ignore the existing broken standard and form their own de 
> facto standard.)
> A standard isn't "correct" just because it's a standard, it's merely 
> something that a committee has agreed to do. In other words, it's a 
> compromise. Now, such compromises might be good and useful, or they might 
> combine the worst of all opinions. Just because something is standardized 
> doesn't make it the right thing to do. If you want proof of this, I give 
> you the recently approved ISO standard for Microsoft's so-called "Office 
> Open XML" OOXML file format.
> The standard behaviour of sending bounce and out-of-office messages to 
> the sender works well when sending email to individuals, but for mailing 
> lists it is pointless and counter-productive. Pointless, because the 
> sender can't do anything to fix the problem he's being notified about. 
> And counter-productive, because it is an anti-feature, something that 
> makes the mailing list more unpleasant and less useful. Anyone who has 
> regularly emailed to a large mailing list has surely experienced the 
> frustration of receiving bounce messages from perfect strangers.
> To anyone who wishes to defend the process of sending mailing list 
> bounces back the sender, ask yourself this: what do YOU do with such 
> bounces when you receive them? If you ignore them or delete them (whether 
> manually or via a procmail recipe or some other automatic system) then 
> what benefit does the standard behaviour offer?

I think you misunderstand. He's referring to the Sender header, not the
>From header. The messages the listbot sends out have a Sender header of
" at" (supposing the
subscriber's email address is user at Bounces should be
directed to the bitbucket or list admin or whatever, not the user in the
>From header. just has a broken mail server.

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