[DECtalk] Corine isn't getting some of our messages

[Jayson Smith]

Hi,

This morning I woke up to a Mailman administration notice that Corine's 
subscription had been disabled due to too many bouncing Emails. By the time 
I tried to enable her subscription again, it appears she received and acted 
upon the message the list software sends when this happens. What is causing 
her address to bounce certain messages is not totally clear to me. It seems 
to me to be a misconfiguration either at a mailserver responsible for 
delivering mail to her mailbox or at my mailserver. However, her domain 
seems to be the only one giving trouble. As far as I know, Mailman only 
attempts to send any given message once. If it bounces, the bouncing member 
simply doesn't see that particular message, and probably doesn't even know 
there was a message sent, unless that bounce triggers an automatic 
subscription disabling. So just know that Corine might not receive any 
particular message, and I don't know if there's anything I can do about it. 
I'm CCing this to her so she'll know what's going on. Corine, if you'd like 
to see the actual bounce which triggered your subscription to be disabled, 
let me know and I'll get it to you.

Just for reference, here's a summary of the bounce processing rules. Every 
member has a bounce score, which in a perfect situation is zero. Any time a 
message bounces and the mailing list software can understand which member 
bounced the message, that member's bounce score is increased by one. The 
bounce score increase will only happen once per day, no matter how many 
bounces are received for that member on that day. Should the bounce score 
ever hit five, that member's subscription is disabled. If this happens, they 
get a message explaining why their subscription was disabled, and how to 
enable it again. I think this message is sent three times, each seven days 
apart. If, after seven days past the last such message, the member in 
question still hasn't enabled their subscription, the bouncing condition is 
considered to be permanent and the member is unsubscribed outright. Finally, 
if seven days go by without a bounce from a particular member, that member's 
bounce score is seen as stale and reset to zero. The upshot is, what it 
takes to disable a member's subscription is for them to bounce at least one 
message a day for five days, with there never being a seven-day period of no 
bounces from that member.
Jayson