I have exchange 2000 on 2 sites. someone from the internet is using myusers@mydomain and sending viruses to my distribution lists/users. Does anyone know how to disable distribution lists=exchange enable security groups ,that they will not recieve email's from outside of the organization (the internet)but to use them only inside the company and between sites in other wards to disable their smtp on the connector to the internet (maybe to create new connector with different port etc..)