Here is a way to set exim as a smarthost
dc_eximconfig_configtype='smarthost' smarthost='shebangthedolphins.net' dc_other_hostnames='' dc_readhost='' dc_relay_domains='' dc_minimaldns='false' dc_relay_nets='' CFILEMODE='644' dc_use_split_config='false' dc_hide_mailname='false' dc_mailname_in_oh='true' dc_localdelivery='mail_spool' dc_local_interfaces='127.0.0.1' dc_smarthost='shebangthedolphins.net:465'
root:~# update-exim4.conf
Contact :