Re: exim4 and SSH tunneling

[bkhl@elektrubadur.se (Björn Lindström)]

Alex Malinovich <demonbane@the-love-shack.net> writes:

> You could just use an SSH tunnel FROM port 25 on localhost TO port 25
> on the smarthost. For example:
>
> ssh -L25:localhost:25 -N your.smarthost.org
>
> That way anything that goes out on port 25 on your local system will
> come in on port 25 of the remote system. So exim will still answer it
> as a default SMTP connection.

Excellent, though I assume you meant -L25:my.smarthost.org:25 there.

For the benefit of googlers, here's the solution I arrived at.

I created a user called smtp-tunnel on the smarthost, and gave root on
the client machines rights to log into that machine with a key. Then I
run

sudo autossh -f -N -L 25:nuala.thaning.se:25 smtp-tunnel@nuala.thaning.se

After that, I just 'dpkg-reconfigure exim4-config' to have it use
nuala.thaning.se as a smarthost.

Lots of thanks for the hint.