Mark Sapiro writes: > On 3/22/26 5:00 AM, Brian McCarthy wrote: > > She never gets the message back at her email. > > > > Checking the whm mail logs it shows it was delivered to her > > outlook email address successfully.
Bravo! That's exactly what we need to know. Thanks! As Mark writes, this is not something Mailman is doing. This is entirely within the recipient's mail system (who is also the sender in this case, of course[1]). When the remote system says "250 OK" (that means Mail Accepted), it has accepted full responsibility for delivery of that message (until something else accepts full responsibility, of course). It could be that that remote system is accepting it, then 1 deciding it is spam, and discarding it 2 deciding it is a duplicate of a mail it has stored, usually in sent, and discarding this copy 3 putting it in the user's spam/junk folder 4 filtering it to a folder according to a user setting 5 forwarding it to another address according to a user setting 6 discarding it according to a user setting. (I'm not sure that's all the possibilities! Email is complicated.) Only the recipient's postmaster can confidently assess #1 and #2. Most mail clients have a search function the user can use to find messages stashed in unexpected places as in #3 and #4. The user would need to check their own settings for #5 and #6. For #3-#6, the user is going to need to do that, possibly with advice from their postmaster or technical staff. Recipient email providers often check that the From address in the message header is valid, by looking for a signature from the sending system. If there is no valid signature, and the receiving system judges by their own criteria that it is spam, some will accept the mail and then discard it. Mailing lists have three ways to mitigate this issue: 1 Set "DMARC Mitigations" in the mailing list's settings, the most popular of which is to edit the "From" header to indicate the identity of the author, but replace the email address with another. (Usually that is the list address, and often the Reply-To address is set for the convenience of recipients.) 2 DKIM sign outgoing messages from the mailing list (this should be done by the mail server, and Mailman has no feature to do it). 3 ARC seal messages sent through the mailing list. This involves checking if the identity of the sender can be validated, and providing a signed report of such authentication checks. This should be done by the MX (the provider's mail server that accepts and sends email with the public Internet). None of these are foolproof, but they're considered best practice in the face of email providers who accept and discard. Microsoft and Google are known to provide ARC seals, and I believe Yahoo does too. So they are likely to also put some weight on them, even for "small, new" domains. And of course they keep profiles, so as you send more clean signed and sealed mail your reputation gets better. Steve Footnotes: [1] Note that for many large email providers, the sending system and the receiving system may be different servers. Also, even if the receiving system knows who its "own senders" are, most mailing lists necessarily destroy the "signature" that proves it was sent by an "own sender" by adding footers with list information and list tags in the subject. -- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan ------------------------------------------------------ Mailman-Users mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/mailman-users.python.org/ Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: https://www.mail-archive.com/[email protected]/ https://mail.python.org/archives/list/[email protected]/ Member address: [email protected]
