Can anyone help me with constructing sendmail rules for limiting spam? Assuming that name of my domain is my.domain.com, I want to use following rules:
If BOTH sender and recipient address is from my.domain.com, message should be rejected (sendmail server only relays messages between my internal exchange server and outside word, so sending messages between users from my.domain.com always occour on exchange server and never on sendmail server)
If recipient list contains AT LAST ONE invalid address, whole message should be rejected (even for valid recipients addresses)
If sending server uses HELO message with bogus domain name (other than domain of this server), message should be rejected
Any server attempting to send mail to dedicated address (f.e. email@example.com), should be automatically blacklisted
Any other suggested rules ...