--On 7 June 2006 23:32:01 -0500 Brad Knowles <brad@stop.mail-abuse.org> wrote:
At 2:35 PM -0400 2006-06-07, Barry Warsaw wrote:
Totally agree. OTOH, don't most MTAs provide /some/ way to call external programs on messages at various points in their workflow?
Sendmail has milter, and that has now been brought into postfix (as of 2.3), but I can't speak for any other MTAs. What would need to happen would be a custom program would have to be written for each MTA to interact with it in the way that MTA works, but which has a deep understanding of Mailman and the configuration for each list and recipient, and could effectively do a "dry run" for each message.
No, that's not true. What's required is that Mailman provide a simple API to allow MTA developers to ask Mailman whether a particular sender is permitted to post to the list. Holding rosters (a v3 proposal) in open databases would solve this problem - at least for Exim.
Although Mailman is capable of filtering on other factors, I don't think the number of cases is significant. However, it might be possible to extend the API to provide information on other list policies.
Of course, this would have to happen after the anti-spam/anti-virus milters, and then some sites are going to use accept & scan techniques as opposed to milter, so there may need to be multiple different "MTA adapters", even for a particular MTA.
If an MTA is doing accept and scan, then none of this is relevant. If the MTA doesn't query Mailman BEFORE accepting the message, then there's never any point in doing it at all.
-- Ian Eiloart IT Services, University of Sussex