On Thu 22 Feb 2018 at 11:58:18 -0600, David Wright wrote: > On Mon 19 Feb 2018 at 18:39:02 (+0000), Brian wrote: > > On Mon 19 Feb 2018 at 10:23:56 -0600, David Wright wrote: > > > > > $ cat /etc/mailname > > > alum > > > > Debian's exim4 README says that mailname should be a FQDN. I find that > > useful for sending mail to "anotheruser". > > Sorry, but I haven't been able to work out what you mean. > Is "anotheruser" a username on the same system, somebody or > some machine on the LAN, or something different?
Exim will qualify all unqualified addresses with mailname. "anotheruser" could be a user on the system or have an email account elsewhere. With mailname as gmail.com a mail sent to or cc'ed to tom123 would go to tom...@gmail.com. > This is a genuine query. If I'm missing out on some useful aspect > of writing in a domain, I'd like to know what it is so I can try > using it. (I have a spare domain registration handy as it happens.) The mailname needn't be the canonical_hostname, although exim will indeed set it up with this when it is installed and mailname does not exist. Easily changed. > > But mailname has nothing to > > do with domain as enquired about by Jeremy Nicoll. > > The contents of /etc/mailname is the answer to this question: > "It should be the single, fully qualified domainname (FQDN)." > so, because the domain is empty, the FQDN will be the same as > the hostname. I was merely showing that to be the case here. Yes. I don't think this disadvantages the majority of users. It is only when setting up an MTA that some thought has to be put into what purpose you want mailname to serve. A single word entry, the hostname, say, would not suit me. > As pointed out elsewhere, mailname can be used to generate > Message-IDs (mutt does) which might not be globally unique, A Message-ID is not used to transport a mail, so how it is generated is not of great importance. As it happens, I generate my own through mutt. > not something to concern most home users, and it can be > mitigated. It's also used as the envelope-from, it appears, > between the mail client and exim which can rewrite it. That's exim qualifying an unqualified address. > I guess that if you submit mail directly from, say, mutt to > a remote smarthost, it would be a good idea to place an > email address into /etc/mailname. I think it is always a good idea to have a FQDN in /etc/mailname, irrespective of what is in /etc/hosts. -- Brian.