I swear I used to get the exactly text of the bounce message when email to a list member bounced, but I'm not seeing it any more. Is there a setting I've overlooked? I've turned on "*Notify owner on bounce increment"* which was off for some reason.
I just had 24 users bounced off a mailing list this morning for excessive bounces, and I can only think their ISP suddenly took exception to my setup somehow. It would have been nice to have to a warning when the first bounce happened.
-- Paul Tomblin
On June 8, 2026 4:31:31 PM PDT, Paul Tomblin via Mailman-users <mailman-users@mailman3.org> wrote:
I swear I used to get the exactly text of the bounce message when email to a list member bounced, but I'm not seeing it any more. Is there a setting I've overlooked? I've turned on "*Notify owner on bounce increment"* which was off for some reason.
With "Notify owner on bounce increment" set to Yes, the list owner should receive a notice containing the bounce DSN whenever a user's bounce score is incremented. Since it was off for some reason, these would not have been sent. The other relevant settings are "notify owner on disable" and "notify owner on removal". The disable notice should also contain the DSN. What were these settings?
I just had 24 users bounced off a mailing list this morning for excessive bounces
Removed or just had delivery disabled? If the latter, I can only think that both the bounce increment and disable notice settings were off.
, and I can only think their ISP suddenly took exception to my setup somehow. It would have been nice to have to a warning when the first bounce happened.
And you should have gotten it, but the setting was off.
-- Mark Sapiro <mark@msapiro.net> Sent from my Not_an_iThing with standards compliant, open source software.
Paul Tomblin via Mailman-users writes:
I swear I used to get the exactly text of the bounce message when email to a list member bounced, but I'm not seeing it any more. Is there a setting I've overlooked?
You've probably seen them. I do get them in the case where an administrative action (disable delivery or unsubscribe) is taken, assuming that the bouncing site provides one ("notify on increment" is off here). That's a function of the last hop MTA before the rejecting MTA, which is never Mailman (Mailman 3 is assumed to use a separate MTA for outgoing mail, I guess if you know what you're doing you could probably configure it to send directly). There isn't necessarily any bounce message: a Sufficiently Smart[tm] MTA may be relaying to the remote while Mailman is still connected, and all you'll get is the remote's status.
I've turned on "*Notify owner on bounce increment"* which was off for some reason.
That's default, I think because starting at a couple hundred suscribers it's just a spam source for the list owner. Note that even if you've got "notify on increment" "on", many of the bounces may be invisible, because only the first bounce in a 24 hour period is counted. The rest are just discarded. On an active list, that could be dozens.
I just had 24 users bounced off a mailing list this morning for excessive bounces, and I can only think their ISP suddenly took exception to my setup somehow.
Do you mean they're all at a particular ISP? The simplest thing to do in that case is to check their policy page if they have one, and then to ask postmaster@ISP.
Also, on the Mailman lists, disable events seem to come in spates, with almost all of them being some variation on "no such user".
If the ISP is mad at *you*, you usually won't find out *why* from the DSN, although some will tell you if it's DMARC. You'll just get a "550 5.7.1 Administratively denied" or similarly opaque reason. The cases where you do find out why is when the status is something like "account deleted" or "mailbox full", which aren't your problem.
It would have been nice to have to a warning when the first bounce happened.
Now that you've turned on "notify on increment", you will. But I think you'll find that it's just an annoyance, as bounces are frequent (at least on larger mailing lists), but rarely an issue you can correct.
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan
On Tue, Jun 9, 2026, at 5:25 AM, Stephen J. Turnbull wrote:
Paul Tomblin via Mailman-users writes:
I swear I used to get the exactly text of the bounce message when email to a list member bounced, but I'm not seeing it any more. Is there a setting I've overlooked?
You've probably seen them. I do get them in the case where an administrative action (disable delivery or unsubscribe) is taken, assuming that the bouncing site provides one ("notify on increment" is off here). That's a function of the last hop MTA before the rejecting MTA, which is never Mailman (Mailman 3 is assumed to use a separate MTA for outgoing mail, I guess if you know what you're doing you could
I use Postfix for my MTA, and like I said I swear I used to see the DSNs before, but this round I’m not seeing them. One wrinkle is the fact that I’m hosted on Linode, and one of the big RBL providers has a bug up his ass about Linode and so instead of just blacklisting the instances that produce spam, he’s basically blacklisting all of Linode. And because of that, I relay my outgoing mail through a friend in Norway. I wonder if that relay has started swallowing the bounce message while still returning the bounce status?
I did, however, get a plaintive email from a little old lady on the list who said “But I don’t want to unsubscribe from the list”. So I guess she at least got her “you’ve been removed’ email. Which again, increases the mystery.
This particular round of “too many bounces” disables all happened in a matter of an hour or so, preceded a couple of days earlier by some others. Does mailman bundle those up and process them all in a batch?
-- Paul Tomblin
Paul Tomblin via Mailman-users writes:
I use Postfix for my MTA, and like I said I swear I used to see the DSNs before, but this round I’m not seeing them.
Default is "notify on increment" = "off", "notify on disable" = "on", "notify on unsubscribe" = "on". Maybe you're remembering Mailman 2 since it's only been about 1/2 year, and you haven't had disable/ unsubscribe since then? All those settings are in the "bounce processing" pane of the settings tab.
One wrinkle is the fact that I’m hosted on Linode, and one of the big RBL providers has a bug up his ass about Linode
My outgoing MTA is Linode, and I'm not seeing that with IPv4. I did have to configure Postfix to prefer IPv4 over IPv6, because one of the big RBLs checks prefix, and if you're not at least a /64, it blocks you. I've also had trouble with Microsoft, but so far it usually forgets I'm evil in a week or so, and if I'm really in a hurry to get mail through their automated IP unblocker does the job in 3 minutes or so. I am not running lists myself at the moment, though.
I wonder if that relay has started swallowing the bounce message while still returning the bounce status?
It could be that it doesn't produce one. However, I'm pretty sure that Postfix will produce one that just says "this is the status, the message data is attached below" with no attachment. So you should be seeing *something* if Mailman is configured to notify on those events.
I did, however, get a plaintive email from a little old lady on the list who said “But I don’t want to unsubscribe from the list”. So I guess she at least got her “you’ve been removed’ email. Which again, increases the mystery.
That does suggest that her provider, at least, doesn't like your list traffic for some reason. It's also plausible that recipient-side problems get resolved just in time for the "you've been removed" email to succeed. I know I've heard that issue before.
This particular round of “too many bounces” disables all happened in a matter of an hour or so, preceded a couple of days earlier by some others. Does mailman bundle those up and process them all in a batch?
Only in the sense that they're all likely to trigger on the same post because of the "one increment per day" algorithm. I think I mentioned earlier, I do see bunching of disable/unsubscribe actions on the Mailman lists. I suspect it's just a matter of a dry spell, then enough posts on a daily basis that all the bounce counts get incremented together (unless all the recipients that get disabled/unsubscribed are managed by the same provider).
-- Paul Tomblin
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This message sent to steve@turnbull.jp
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan
On 6/9/26 9:13 AM, Paul Tomblin via Mailman-users wrote:
I use Postfix for my MTA, and like I said I swear I used to see the DSNs before, but this round I’m not seeing them.
What were the list settings for Notify owner on bounce increment and
Notify owner on disable during this round. You said in an earlier post
that Notify owner on bounce increment was off. If Notify owner on disable was also off, that would explain why you didn't get these
notifications.
One wrinkle is the fact that I’m hosted on Linode, and one of the big RBL providers has a bug up his ass about Linode and so instead of just blacklisting the instances that produce spam, he’s basically blacklisting all of Linode. And because of that, I relay my outgoing mail through a friend in Norway. I wonder if that relay has started swallowing the bounce message while still returning the bounce status?
If it returned a bounce status to the sending MTA, the sending MTA would have generated a bounce DSN. Further, if the notification settings were on, you would have received notices even if the DSNs were unavailable for some reason.
I did, however, get a plaintive email from a little old lady on the list who said “But I don’t want to unsubscribe from the list”. So I guess she at least got her “you’ve been removed’ email. Which again, increases the mystery.
This particular round of “too many bounces” disables all happened in a matter of an hour or so, preceded a couple of days earlier by some others. Does mailman bundle those up and process them all in a batch?
No, they are processed at intervals defined by the bounce runner's sleep_time as defined in mailman.cfg with a default of 2 minutes.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
participants (3)
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Mark Sapiro -
Paul Tomblin -
Stephen J. Turnbull