exim4 relay domains

root@gregk:/etc/exim4# pwd
/etc/exim4
root@gregk:/etc/exim4# grep -H -r "relay_domains" .
./exim4.conf.template:# relay_domains. The most typical use for relay_domains is to control
./exim4.conf.template:# here so that mail to relay_domains is handled separately.
./update-exim4.conf.conf:dc_relay_domains=''
./conf.d/router/200_exim4-config_primary:# relay_domains. The most typical use for relay_domains is to control
./conf.d/router/200_exim4-config_primary:# here so that mail to relay_domains is handled separately.