On 2006-07-28 at 21:31-05 Brad Knowles brad@stop.mail-abuse.org wrote:
Unfortunately, there are a whole host of seriously broken MTAs out there, and seriously broken configurations of otherwise good MTAs, and many sites return totally bogus status codes. In many cases, site admins will blindly copy stuff from somewhere else that was horribly broken to begin with and won't understand what's wrong with it before they do the cut-n-paste operation.
Perhaps, but we cannot solve this problem, and there's a fine line between working around stupidity and coddling it.
That said, I would not be opposed to seeing more data on this subject, and possibly giving site admins or list admins an option they can enable that would allow Mailman to pay attention to the status codes. Once that's out there, we could let various people try it out and see how it works in the field, and I would be a very happy guy if I were to be proven wrong in this case.
What further data do you wish to see? I think I've documented the problem well enough. There's no way we know many horribly broken sites are out there.
On 2006-07-31 at 10:56+01 Ian Eiloart iane@sussex.ac.uk wrote:
I don't see how that could create a problem. The worst thing that could happen is that someone remains subscribed to a list when they should not. Alternately, they could be unsubscribed because their MTA is returning the wrong error codes - but then that would give their postmaster a good reason to fix the error codes. In this case, they'd be unsubscribed as things stand anyway.
Right: the only risk is that bounces coming from a subscriber at a broken site might be ignored, because they look like they're being generated based on the content of certain messages.
IMHO, this risk is negligible. If the operators of the broken site in question get annoyed that Mailman keeps trying to send messages to a non-existent address, they should fix their broken site.
As a compromise, I suggest adding this feature as a bounce processing tunable; for example, "content bounce handling":
Setting:
How should Mailman handle bounces that appear to be related to
content?
Description:
Sometimes a message to a subscriber bounces due to the content
of the message, not because the subscriber's address is
invalid. This option controls how Mailman handles bounces
that appear to be related to the content of messages.
Picking "count the bounce" will cause Mailman to count any
bounce against the bounce threshold, regardless of the reason
why the message bounced. The advantage of this option is that
it is least likely to "miss" bounces. The disadvantage of
this option is that it penalizes subscribers at sites that
correctly indicate why a message bounced.
Picking "forward the bounce to the list owner" will cause
Mailman to forward bounces that seem to be related to the
content of specific messages to the list owner. The advantage
of this option is that the owner will be able to review the
bounce and take appropriate action; the disadvantage is that
the list owner might be overwhelmed by bounces.
Picking "ignore the bounce" will cause Mailman to ignore
bounces that appear to be related to the content of specific
messages. The advantage of this option is that subscribers at
sites that correctly indicate why a message bounced won't be
penalized. The disadvantage is that if a misconfigured site
erroneously indicates that *all* messages are due to content,
then Mailman will never detect bouncing subscribers at that
site.
Choices:
[X] Count the bounce against the threshold.
[ ] Forward the bounce to the list owner.
[ ] Ignore the bounce.
Comments?
James