On Sat 26 Sep 2020 at 10:50:11 (+0300), Andrei POPESCU wrote: > > > > It ought to—I have no idea whether mutt can even use it, though > > I suppose it's possible—but AIUI the file belongs to exim4-config. > > It "needs" a dot to prevent your being nagged about its lack, and > > having an @ in it could screw up any use exim makes of it. > > (I use it to set exim's HELO.) So I thought it best to mention it. > > As far as I recall[1] /etc/mailname is Debian specific[2], to be used by > all softwares (typically MTAs and some MUAs like mutt) that need a > domain part to construct a full e-mail address, when one isn't provided. > > [1] too lazy to check where it's documented, quite likely in Debian Policy > [2] as in Debian specific patches to support it
Your ¹ is correct. Specifically, from file:///usr/share/doc/debian-policy/policy.html/ch-customized-programs.html#mail-transport-delivery-and-user-agents If your package needs to know what hostname to use on (for example) outgoing news and mail messages which are generated locally, you should use the file /etc/mailname. It will contain the portion after the username and @ (at) sign for email addresses of users on the machine (followed by a newline). Such a package should check for the existence of this file when it is being configured. If it exists, it should be used without comment, although an MTA’s configuration script may wish to prompt the user even if it finds that this file exists. If the file does not exist, the package should prompt the user for the value (preferably using debconf) and store it in /etc/mailname as well as using it in the package’s configuration. The prompt should make it clear that the name will not just be used by that package. For example, in this situation the inn package could say something like: Please enter the "mail name" of your system. This is the hostname portion of the address to be shown on outgoing news and mail messages. The default is syshostname, your system's host name. Mail name ["syshostname"]: where syshostname is the output of hostname --fqdn. So on this system, its value is axis.corp, which you can see in the header of this email. It certainly shouldn't be an email address, containing a local part and @. I wasn't aware that there is a (somewhat old) wiki page which is supposed to list all the MTAs (which I understand as including programs which submit mail using SMTP) and how they interpret /etc/mailname. For some reason, mutt is treated under the heading for exim4. Half a dozen headings have no information listed, and I don't know whether there are packages/programs missing altogether. There are at least three or four important fields that involve various interpretations of "from-ness": EHLO, envelope (MAIL_FROM), From: and Sender:. (That's ignoring Resent* and so on.) How these relate to each other is not straightforward, particularly for home users' machines, and their values can be an important factor in whether their emails make it into the Internet and on to their destination. What works for one person may not for another. (That's also ignoring intranet emails.) Having decided on their values, it's also non-trivial to work out how to set each one: the documentation is widely scattered and sometimes missing. It would be a help to have a wiki page that consolidated that information. Cheers, David.