[Mailman-Developers] Re: [Mailman-Users] Bounce Options

Nigel Metheringham Nigel.Metheringham@VData.co.uk
30 Nov 2001 11:06:36 +0000

On Thu, 2001-11-29 at 23:55, Dan Wilder wrote:
> So what's a reasonable intent for bounce handling?  
> Here's a sketch.  No doubt I misunderstand important points.
> Perhaps others would be kind enough to comment.
> Presuming the list is configured for automatic bounce handling
> at all, it would seem reasonable to claim that there are 
> circumstances under which bounce handling might unsubscribe or 
> disable mail to a subscriber.

Definitely.  In general I (as list admin) want almost zero involvement

> The sporadic bounce probably shouldn't cause this sort of action.
> So, there should be some forgiveness mechanism in place.

Yes - I occaisionally bounce stuff from bugtraq because we have a filter
on that bounces executable content (ie outlook virus hacks), but it also
bounces some exploit code :-)
So I sometimes bounce 10% of the messages in a day.

> Several bounces over a short period of time might reasonably
> be forgiven, or treated as a single bounce.  Many situations
> that will cause a bounce involve some misconfiguration which
> the conscientious sysadmin will shamefacedly correct as soon as
> it is brought to his or her attention.  A heavily trafficked
> list might not want to unsubscribe even members who cause several
> bounces, providing these fall within a short period of time.
> Several bounces over a longer period of time might be cause
> for suspension, even if posts are accepted between.
> The existing bounce handling makes some distinction I don't
> understand between "fatal" bounces and "nonfatal" bounces.  
> Is this "no such user" versus "host busy", for example?

SMTP has immediate and retryable errors

For an announce list - I have a few (similar to mailman-announce) which
have traffic in single digits per month (if that high), the rules may
need to be different - 2 bounces from a user in 5 days is going to be
close to impossible to achieve for example :-)

Unfortunately its hard to identify correctly delivered messages - so you
cannot easily use a "if a message is delivered correctly, reset the
death counter" approach - one UK ISP routinely bounces mail to their
users that has not been picked up after 30 days (and their bounce
messages are currently unparsable).