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Re: Exim4 (mis)configuration for smarthost (Was: Re: How to disable TLS in exim4 client part?)

On Tue, 03 Jan 2012 21:30:22 +0100
"Alois Mahdal" <Alois.Mahdal.1-NDMAIL@zxcvb.cz> wrote:

> Thankfully, I have found that using -v (verbose) option for tests
> gives me enough insight to communication (about what I expected to
> find after disabling TLS).
> And the lines I like the least are:
>    SMTP>> EHLO gebba.aloism.test.local
>    ...
>    SMTP>> MAIL FROM:<aloism@gebba.aloism.test.local> SIZE=1467  
> AUTH=aloism@gebba.aloism.test.local
>    ...
> It seems that exm4 does not rewrite addresses as I wish according to
> /etc/exim4/email-addresses:
>    aloism@localhost: correct.sender@mydomain.cz
>    aloism@gebba.aloism.test.local: correct.sender@mydomain.cz
>    aloism@gebba: correct.sender@mydomain.cz
>    aloism: correct.sender@mydomain.cz
> Neither of these lines work.  But manual says:
>    (sender addresses) "...are rewritten for users that appear  to be
> in the local domain..."
> and my domain (in resov.conf) is different from
> gebba.aloism.test.local. Might this be the cause?  That
> "aloism@gebba.aloism.test.local" does not "appear to be in local
> domain"?
Sorry, I can't be of much help in this area, I've never had much to do
with rewriting. The usual thing that needs doing is to change
fred@computer.domain.com to fred@domain.com. I use about a dozen
domains, and they are all named in the entry dc_other_hostnames in my
server's update-exim4.conf.conf (this is specific to exim4 on Debian)
and as long as my email client uses a sender address in one of these
domains, no re-writing is necessary. I could be wrong, but I wouldn't
have thought that resolv.conf would be involved, *nix systems do not
generally confuse local DNS search domain with email domain in the way
Windows does. /etc/mailname is probably more relevant.

This may be of some help:
Exim4 does have extensive test facilities, where you can get some idea
of what should happen to an email without actually sending it. I
generally only use a small part of it, to test whether emails from some
problematic spam domain will make it past my various acls.

Remember the most basic exim4 configuration gotcha: you can use either
individual small files for configuration in /etc/exim4/conf.d, or one
large one, the /etc/exim4/exim4.conf.template. You decide which in the
initial configuration dialogue, which you can do again with
dpkg-reconfigure exim4. If you make a configuration change in the
wrong place, nothing will happen. Most of us only do it once...

Certainly if you use an invalid domain such as .local and the system
tries to send the email using that domain, many people will reject
it. Most mail servers will check the sender, at least at the level of
the domain. I use exim4 as my system mail server, and it is
configured to do exactly that. I could ask it to check that the
sender actually exists at the sending domain, but that's not really
worth the extra trouble. But if an email fails for this reason, the
SMTP transaction will be interrupted, and the sending server will
report the reason back to the sender. 


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