On Wed, 25 Aug 2021, Sabahattin Gucukoglu via Exim-users wrote:
> What about if I extent this setup so that my mailer machine only
> makes outbound connections to the proxy host—can I still receive
> inbound mail, through a forwarded port perhaps? SSH seems like the
> obvious answer, but then I’d lose sender information, yes? I could
> use an inner VPN, perhaps. But something that only carries
> application-layer traffic would be nicer. Exim supports SOCKS, but
> not the bind method—perhaps that would be useful.
Sounds as though ETRN might be what you want.
The "real" server connects to the secondary with SMTP, gives the command
"ETRN" and the secondary then sends any waiting email down the connection.
I've never tried this so can't say much about the pitfalls or other details
but it appears to have been designed for dial-up mail servers.
--
Andrew C. Aitchison Kendal, UK
andrew@???
