If we point our MX record to Spamclam, will it hold our mail?

No. While Spamclam's filters do comprise the final “hop” a message takes en route to your network, we do not have the capabilities to intercept or review email. The Spamclam message processing centers, which becomes your primary MX record, act as proxies when receiving your inbound email. Messages are filtered in real-time as they are being simultaneously delivered into your messaging environment. Because MX Logic’s service is proxy-based, your messages are not stored to disk in order to be filtered, where they can be lost if the disk is damaged or corrupted (this can occur with solutions that use store-and-forward technology). In fact, MX Logic’s technology introduces more security by cloaking the location of your messaging servers and removing anonymous SMTP connections.