The mailing list for listmasters using Sympa

[John Roberts <address@concealed>]

Hi Sympa folks,

For those who run mailing lists with one of the various Send scenarios
that use moderation, or those who run mailing lists that reject messages
from non-subscribers and send a rejection message to the sender, have
you ever had your mail server end up on a blacklist because of this?

I ask this because I think that the automatic messages generated by
Sympa in these cases could be considered Backscatter (they are messages
sent back to a sender after the original SMTP conversation ended with
the message being accepted) and I'm concerned that our mail servers
could end up on a DNSBL.

When I set up a mailing list as moderated and then test it, my test
sender immediately receives a reply indicating that the message is in a
moderation queue.  When I reject that test message, the test sender
immediately receives another reply indicating that the message was rejected.

I'm concerned that if our moderated mailing lists are ever discovered by
spammers (which I think is inevitable given enough time), and the
spammers start sending spam to these lists using forged sender addresses
(as they would), our Sympa server will start sending unsolicited
moderation/rejection notifications to random innocent bystanders, and
the next thing I know, our mail server is on several DNSBL lists.

The same concern would apply to a list that is configured to reject
messages from non-subscribers, non-list-owners, etc. with a rejection
message.

Is this something I should be concerned about?

Can I prevent moderated lists from sending a "Message distribution"
message when a message is received, and then another one when a
moderator rejects the message?

Thank you!

Cheers, John Roberts
SNOLAB