Florin Pasăre writes: > I would like to ask you where the system
What do you mean by "the system"? Mailman? The mail servers (these are the programs that exchange mail between hosts on the Internet)? Your mail client (the program you use to read and send mail)? "Something" between the author's fingers and your eyes? > gets the names you see in the "sent by" field, What "sent by" field? Do you mean something you see in your mail client? Maybe the From field? (There is no standard "sent by" field for email,) > because sometimes the name doesn't make it clear who is sending the > email and we would like to know if it is something we can control > or change. The mail standard RFC 5322 specifies a "From" field which contains the address of the author and optionally a display name for them. This is set by the author's mail client, and according to the standard should not be changed by anyone else. However, (1) mail clients such as Outlook and Apple Mail frequently change, interpret, or add random stuff to the From field when they display the author's identity, and (2) there is an anti-phishing protocol called DMARC according to which a sending system can request rejection of mail claiming to be from that system unless a valid digital signature is present. Since some things that a mailing list does (like adding unsubscription information as legally required in many places) break the signature, Mailman has an option to change the From field from "Some User <u...@domain.tld>" to "Some User via This List <l...@listhost.tld>". This DMARC mitigation is only used if the list owner explicitly configures it. > Another question is where the system gets the name of the person who > appears in the "reply to" field. According to RFC 5322, that field also should only be set by the author of the original message. However, nonconforming behavior is common, and under certain circumstances Mailman will set that field: 1. By default, Mailman will not touch that field, but will pass it through if it exists. 2. When configured to do so, Mailman will add a fixed address (usually the list's posting address) that the list owner specifies to Reply-To. 3. Alternatively, when Mailman is configured to change the From address to mitigate rejections at subscribers' systems due to the DMARC protocol, Mailman will add the original From address to Reply-To. I think in the case of setting Reply-To to an specific address, the list owner may specifically ask Mailman to remove other addresses. I don't think that any mail servers (such as Postfix or Exchange) ever touch Reply-To. > I've already seen wrong/different than what was expected names > twice using Mail on Macbook. The message is sent, for example, by > Mario Rossi, and the system adds his email address to the cc. I don't recall for sure if there are circumstances where Mailman changes Cc, but I'm pretty sure it never does. I don't think that any mail servers (such as Postfix or Exchange) ever touch Cc, only the originating mail client does. > The problem is the reply-to field, because there one sees the name > of, for example, Claudio Bianchi, which has nothing to do with this > message and so I don't understand why his name appears above the > general address of the mailing list. What do you mean by "above"? Please quote exactly what is on screen. (Sorry, this list doesn't permit screenshots.) > With MS Outlook instead what one sees in the sent-by field is the > following: list name list-boun...@domain.ext on behalf of XXX via list name > l...@domain.ext. By "sent-by field" do you mean the "From" field? That sort of looks like something Mailman might produce, but not exactly (which means Mailman did *not* produce it). I believe in the case of DMARC reformatting Mailman produces the "XXX via list name <l...@domain.ext>" portion, but it will *definitely* not put "list-bounces" anywhere in From. Check that you are quoting exactly. If so, I think that is Outlook hallucinating. Outlook definitely displays garbage under some conditions, and I think I remember this particular problem being an Outlook misfeature. Specifically, it grabs the content of the "Sender" field and puts it before "on behalf of". > Is it possible to have l...@domain.ext instead of > list-boun...@domain.ext? The <list-boun...@domain.ext> is the address Mailman puts in the "Sender" field (normally not displayed by mail clients). If Sender is present in the mail header, mail servers send various administrative messages to Sender rather than From or Reply-To, including non-delivery messages. You do not want to change the "Sender" field to the list-post address, because all those administrative messages would then go to the list, and many would likely be distributed to the subscribers. You do not want to remove the "Sender" field, because without it such messages would go to post authors but they probably cannot do anything useful with them (and sometimes there are many for just one post). > If you have any hints for where to look or any ideas, it would be > great. My suspicion is that you are stuck: the problem is that the mail clients you are using do a very bad job of presenting header information. I'm not going to tell you to change clients, but I can't think of anything you can change in Mailman that would make it work better with Outlook or Apple Mail. If you want to see if there is *anything* we can do: Start by quoting exactly what you see on the screen, and continue to specify the mail client used as you did in this message. The problem is that the mail standard provides a minimum of 6 different ways to specify who sent a message, each with well-defined, unique meaning to mail programs. None of them are called "sent-by", and "good" mail clients report the header fields using the technical names precisely to make conversations like this one go more smoothly. An exact quote of the full header information as presented by the mail client will help us guess more accurately what is going on. Do not say "the system does X" unless you (1) identify which program is doing X and (2) you are quite sure that that program is the one that is doing X. If X is what you see on screen, say that, and what program you are using to view that content. If possible, use an open-source mail client such as ThunderBird to view the message and report what you see there. Outlook and Apple Mail both present the message in ways that make it difficult to understand what the message header actually contains. 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