vi /etc/exim.conf
spamgateway_smarthost_router:
driver = manualroute
domains = ! +local_domains
ignore_target_hosts = 127.0.0.0/8
condition = "${perl{check_limits}}"
transport = spamgateway_smarthost_transport
route_list = $domain mx.smarthost.com::587
spamgateway_smarthost_transport:
driver = smtp
hosts_require_tls = *