Iweb Security Spam Protection: Spamming can be done in many ways from one server.. to prevent it we have to deal with many settings and security aspect. 1) Disable Nobody sender from the server. 2) Disable PHPmail function on server and force customer to use SMTP authentication 3) Scan server for malware. 4) Strict your modsecurity rules ( its related to web server but remember malware or bad scripts travel through the web only. 5) User the RBL list and sender verification 6) Enable SPF and DKIM 7) Limit the per domain/account limit. 8) Configure CSF smartly so you can get alert for each activity from the server. 9) Monitor your email queue may be you can use the scripts to monitor the email queue count 10) Enable SpamAssession and configure it properly ( if cpanel) 11) stop relay from your server. To protect your server from spamming or any other attacks is the continues process, it's not something you build something and leave. You need to have some hand on technical stuff or you may get Managed servers (hope the provider covers it efficiently) else best option would be go for server management companies who can better deal with it as they got hands on on such issues. Thanks, Neemaperl