Re: [exim4] mixed up about terminology
On Mon, 06 Oct 2014 14:06:57 -0400
Jerry Stuckle <jstuckle@attglobal.net> wrote:
>
> That's true - but he has ONLY ONE MTA ON HIS NETWORK. So there are no
> other hosts to relay for.
You only need one Internet-facing MTA. It's normal for Windows hosts
not to have an MTA at all, and it's common for MTAs on Linux hosts to
deal only with system mail. My Linux MUAs all use the network
smarthost, not the local machine MTA. This is absolutely necessary,
since I send mail direct and don't use an external smarthost, but even
if I did use a further smarthost, I want my own to log everything in
and out of the network. My firewall expressly forbids the forwarding of
port 25 either to or from the network hosts, everything in my network
relays through exim4.
>
> dc_relay_nets is NOT there to relay for MUAs. The MUA just connects
> to the MTA and passes the traffic.
>
You seem to have this idea that MUAs don't connect to MTAs by SMTP.
That may be the case if they are both running on the same host, but
with, as far as I know, the sole exception of of Outlook/Exchange using
MAPI, all MUAs connect to MTAs on other hosts by SMTP. Even fetchmail
connects to the MTA on its own host by SMTP. And if the mail is
accepted, but doesn't have a local mailbox, it is *relayed* to the SMTP
server which does contain its destination mailbox.
And trust me, if I don't have my networks specified in dc_relay_nets,
the mail goes nowhere. When I started to connect in from outside using
a routed VPN, I needed to add the VPN network block to dc_relay_nets,
and it took me a little while to realise what the problem was.
Observation trumps theory every time.
--
Joe
Reply to: