Which version is your sendmail package (`rpm -q sendmail')? sendmail version 8.9.3
sendmail should reject relaying attempts with the latest distributions.
Make sure you did not use a sendmail.cf file from an older distribution! The file that you need is /etc/mail/access (don't forget to `makemap hash /etc/mail/access < /etc/mail/access.db'!). I always rehash my db files after making changes. Besides I have also noticed that it seems to ignore certain files like genericstable.db It reads the virtuser table but access and relay-domains no way yet the lines are there in sendmail.cf lines like # Generics table (mapping outgoing addresses) Kgenerics hash -o /etc/mail/genericstable.db
# Virtual user table (maps incoming users) Kvirtuser hash -o /etc/mail/virtusertable.db # Access list database (for spam stomping) Kaccess hash -o /etc/mail/access.db