content_filter = smtp-amavis:[127.0.0.1]:10024

127.0.0.1:10025 inet n  -       n     -       -  smtpd
    -o content_filter=
    -o local_recipient_maps=
    -o relay_recipient_maps=
    -o smtpd_restriction_classes=
    -o smtpd_client_restrictions=
    -o smtpd_helo_restrictions=
    -o smtpd_sender_restrictions=
    -o smtpd_recipient_restrictions=permit_mynetworks,reject
    -o mynetworks=127.0.0.0/8
    -o strict_rfc821_envelopes=yes

@local_domains_acl = ( ".$mydomain", '.myhost.com );
#  The above prevents from the scanning of *out-going* email (if you have some out-look users, you want to have your out-going mail scanned, haha

$warnvirusrecip = 1;
$warnbannedrecip = 1;
#  You may wish to have your users be notified at least when they are send emails with viruses

$sa_tag_level_deflt  = 3.0;
$sa_tag2_level_deflt = 5.0;
$sa_kill_level_deflt = 100;
$sa_spam_subject_tag = '***SPAM*** ';
#  Some nice spamassassin settings.  Especially useful is the last, where you get the email with the ***SPAM*** thing in the subject.  It sticks out like a sore thumb and can easily be avoided. (If you want to do something similar with emails that have viruses, just ask)