On 01/31/2018 11:57 AM, Peter Münster wrote:
On Wed, Jan 31 2018, Mark Sapiro wrote:
I have verp_delivery_interval = 10 ...
Which says only every 10th message will be VERPed. You want verp_delivery_interval = 1 to VERP every message.
Why? The smtp relay host would get much more outgoing messages. With verp_delivery_interval = 10, only 10% of the messages would be personalized. Shouldn't this be enough to detect sooner or later, that a recipient address is no more valid? Or is it important, to detect such failure immediately?
Yes, VERP does increase the number of SMTP transactions to deliver the mail from mailman to the outgoing MTA, but in general it has mush less effect on deliveries from the outgoing MTA to the recipient MXs, but with modern hardware, most people seem to find the added overhead of VERP to be minimal. Also, it is possible to have the MTA do the VERPing rather than Mailman. See https://bugs.launchpad.net/mailman/+bug/558067 for a way to do this in Mailman 2.1. There's nothing for Mailman 3, but all that's needed is to configure Postfix to do it and add an appropriate mail_options= to the smtplib.SMTP.sendmail() calls to enable it.
In any case, consider (assuming automated bounce processing is working, which it currently isn't) a list with bounce_info_stale_after = 7 days that gets even a post per day and has a member who is bouncing with a DSN that can't be successfully parsed for the member address (maybe because the bounce is from a forward to a different address) so only a VERPed bounce will be successfully scored.
At some point a VERPed post bounces for this member and the member gets a bounce score of 1. Now, the next 9 posts to this list will not be VERPed and by the time the 10th post bounces it's more than a week since the first bounce and the score is reset so this member's delivery is never disabled.
-- Mark Sapiro email@example.com The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan