[IMail Forum] Stop Spam

[Interinmo]

We are an ISP, we do not have any dail up users, but we do provide hosting services.   We have a problem with bulk emails send through our mail server, Using IMail v5. In the control panel under SMTP security we have the following settings checked: Refuse NULL<> Senders, Check valid sender and Auto-deny possible hack attempts.   Under "Mail Relay Options" we have the "Relay mail for anyone"  checked.   If we check the "Relay for local hosts only" then our users can only send mail through our server to other users from us, and not to anyone else that do not have a domain hosted with us, the same goes for "Relay for local users only".   We cannot provide a service to our customers where they can only send emails to our users, they need to be able to send mail to anyone they like, but we do not want non-clients to send mail through our server.   After 1 year I still have not been able to find the solution to this. Is there anyone out there that can help?   Help is appreciated. ------------------------------- Taco Fleur