Routing all outgoing mails via the outgoing smarthost:
For this you have to edit your Exim configuration file (e.g. /etc/exim/exim.conf).
You have to add in the routers section (after begin routers):
fidocloud_smarthost_router: driver = manualroute transport = spamexperts_smarthost_transport route_list = $domain smtp.fido.net::587 no_more
If you don't want local mail to be forwarded, then make sure the local mail router is before this one.
You have to add in the transports section (after begin transports):
fidocloud_smarthost_transport: driver = smtp hosts_require_tls = *
Finally restart Exim.
Routing specific domain destinations via the outgoing smarthost:
Put the domain in place of the $domain value in the route_list (above). For multiple domains you can use:
route_list = domain.example.com smtp.fido.net::587 ; domain.example.org smtp.fido.net::587