The esteemed Mark Sapiro has said: > > Very persistent as in delaying for more than 5 days, or is your MTA's > retry period shorter than that? > > I'm sure you know what's happening in your case; maybe I'm just lucky, > but I think my Yahoo deferrals/retries always succeed within way less > than 24 hours. > > <rant> > I think Yahoo is wrong in this. If the deferrals are a form of > greylisting, there's no point in deferring more than once. One delayed > retry proves the sending MTA is going to retry and subsequent > deferrals are pointless. On the other hand, if they're never going to > accept the mail, they should reject it outright with a 5xx. The only > result from deferring multiple times and then accepting is to cause > problems for their users resulting from delayed mail and to waste > network resources with all the unnecessary retries. > </rant> > I recognize this pattern in dealing with several of the large recipient sites. Can't recall now, but I think yahoo, hotmail, and verizon all pulled this stunt, and what's happening is not obvious to the Mailman admin who does not have access to sender site logs. I'm using sendmail as MTA, so this scenario is what happens with sendmail.
Rather than bounce the mail with a 5.x.x DSN the recipient site defers with a 4.x.x DSN. Mailman, as an MUA, receives notices sent to listname-bounces that the mail is being deferred, but unless Mailman is set to deliver those messages to the admin, they vanish. The MTA has a timeout (sendmail default is 5 days, I reset to 3) after which it discards mail from the queue and sends a bounce message, which gets processed. After receiving bounces for N days, Mailman sets the address nomail-by-bounce. It becomes obvious to the Mailman admin when the bounce processor sends the bounce notices. Generally, the bounce reminders also get blocked by deferral, so Mailman unsubscribes the acount after the waiting period. To put the frosting on the cake, the recipient doesn't get the "you've been unsubscribed" message, either. In a couple of cases, the bounce messages sent to the sendmail log will start having http links in the message. Only the site administrator who is reading the MTA logs gets to see that, and it's sporadic---not every deferral message has that included. The link is generally to a URL for getting the sender site whitelisted with the big mail operation. Needless to say, the whole thing is pretty invisible to both a Mailman administrator and the recipients. In the meantime, the MTA queues get filled up, the addresses get retried at regular intervals. Consider 5 days of deferrals before the first bounces to Mailman, three more for Mailman to set the user nomail, then three more weeks to the unsubscribe. And of course, the days of deferrals and retries make the mail list look like a spam generator. We're set up here to discard unrecognized bounce messages (that address is a prime spam target), but to get bounce and unsubscribe notices. Hank ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org http://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-users/archive%40jab.org