I just put together something which might be helpful, showing how you
might use Exim on a laptop at an ISP which blocks port 25 outbound,
using SOCKS to connect to an OpenSSH DynamicForward port to send out
email:
https://github.com/Exim/exim/wiki/SocksSSH
* Exim must have been built with SUPPORT_SOCKS=yes in Local/Makefile
* OpenSSH must allow dynamic forwards
* The config extracts are "more than bare minimum"; rather than show
something which might be assembled into a working whole with a lot of
work, but with errors along the way, I've tried to provide complete
working routers/transport/authenticators with how it all plumbs
together.
It's rather neat to see `CV=dane` appear in the logs of Exim on my
laptop, as it uses DNSSEC validation to figure out where to connect to,
but then uses SOCKS to bounce out along an SSH connection to a server
(on another continent) before continuing to connect onwards. Myself,
I'm not leaving that enabled, as I'd rather route the mail correctly
through the Exim on the remote server, so that it gets DKIM-signed.
Hope this proves helpful to some,
-Phil