On Sat 01 Oct 2016 at 21:23:33 +0900, Mark Fletcher wrote: > On Sat, Oct 01, 2016 at 12:36:10PM +0200, mo wrote: > > > > I just did that and now mailing works flawlessly :D > > Just one questions: Why do i need hubbed_host entries? Should it not be fine > > alone to make a entry in /etc/hosts for the machines i want to send mail to > > (I do not operate a dedicated DNS server). > > This is something i dont really understand... > > hubbed_host entries apply only to exim4. I also suspect, but am not > sure, that they are a Debian extension to exim4 in the sense that the > *DEBIAN* exim4 comes configured for them out of the box, while the > upstream exim4 does not. IIRC there is no reference to hubbed_hosts in > the upstream documentation, only in the Debian docs.
Correct. I'll add: the upstream documentation spec.txt.gz covers hubbed_hosts in sections 20.3 to 20.7. It is not obligatory to read it. > They work because the debian config contains a router to handle hubbed > hosts. You can see what it is doing if you search > /var/lib/exim4/config.autogenerated for the text hubbed_hosts. Fine. > If the file is not populated this router is skipped and then exim4 > requires either that the address is the local machine, or that there is > a smarthost configured that it can delegate to, or that it can find an > official MX entry for the target domain by doing a DNS lookup. All of > which will fail for a local box that isn't registered to the world as a > mail server. The thing for Mo to grasp is that exim *always* does an MX lookup, often using the ISP's DNS server. user@server will fail (as has been found out) because the domain "server" is not in the DNS. /etc/hosts is not consulted when the lookup is done. exim can be made to look at /etc/hosts but for such a simple setup it is not worth the effort and would likely lead to a world of pain. -- Brian.
