[NANOG] Re: Mailing list message headers

[Joel Esler via NANOG <nanog () lists nanog org>]

I do not run the list, but I have extensive experience with mailman.. inline:




— 
Sent from my 📱iPhone
> On Mar 8, 2025, at 09:26, nanog--- via NANOG <nanog () lists nanog org> wrote:
>
> Something was up with the headers on this message delivering multiple copies to NANOG. Possibly Thunderbird inserted 
> an extra CC to the list. /This/ message only has To: nanog () lists nanog org and should be delivered once. If so, 
> nothing is wrong the list and it was my fault for not checking the CC header.
>
>
> I'm also seeing most but not all list messages with To: NANOG From: NANOG. To see who actually sent the message I 
> have to check the message source as it's saved in X-MailFrom. Is this the new expected behaviour after the server 
> upgrade?

This is expected based on configuration.  If the list admins want the traffic to stay on the list, as a primary, which 
I recommend, then yes. It should send this way.  The other way to configure mailman is to make the “to” the actual 
sender. The problem with that is, everyone on the list has to reply all. Otherwise, all responses go back to just the 
sender on reply. 
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