I might be asking this question the wrong way, so please bear with me. I
would like to setup Exim as a relay which pretty much passes an incoming
connection to another Exim server, but keeps the connection open until
the final server accepts the message or not (after it checks the
recipient, spam score etc). The scenario would like like this:
[internet] <-> [relay Exim] <-> [inhouse Exim]
Can the smtp router or transport on the relay Exim be configured to keep
the connection open for inbound email until the inhouse Exim accepts or
rejects the email? My current thinking would be to use something like
below on the relay Exim, sitting in the middle - but I can't figure out
if there is an option to tell the smtp driver to wait until the final
delivery and not close the connection, so that it can reject the email
if not accepted by the inhouse Exim:
begin routers
relay_to_inhouse:
driver = manualroute
domains = mydomain.com
route_list = mydomain.com <ip of inhouse Exim>
transport = remote_relay_to_inhouse
host_find_failed = defer
no_verify
remote transports
remote_relay_to_inhouse:
driver = smtp
