vim /etc/mail/access
Connect:localhost.localdomain RELAY Connect:localhost RELAY Connect:127.0.0.1 RELAY Connect:example.com RELAY
/etc/mail/accessを記述した後、下記コマンドでハッシュにします
# makemap -v hash /etc/mail/access.db < /etc/mail/access key=`connect:localhost.localdomain', val=`RELAY' key=`connect:localhost', val=`RELAY' key=`connect:127.0.0.1', val=`RELAY' key=`connect:example.com', val=`RELAY'