Overview

While the Kerio Connect Anti-spam feature is enabled, the internal emails might be wrongly marked as Spam. It can be considered as false-positive alert or misconfigured non-recommended Spam Filter settings.

Messages flagged as spam will be automatically sorted to the Junk/Spam folder, which is a default folder belonging to each user of Kerio Connect.

Prerequisites

Access to Kerio Connect Administration

Solution

1. Navigate to Configuration -> Spam Filter. Make sure the Rating of messages sent from trustworthy relay agents defined in SMTP relay options is disabled. This includes devices in your internal network such as scanners or fax machines. The backup MX server should NOT be in this IP address group.
   
2. The corresponding option can be also modified using mailserver.cfg. Variable CheckRelayedMessages under the SpamFilter table should be set to 0 (zero).
   
   For more information about the modification, please refer to modifying mailserver.cfg.
3. (Optional) The recommended spam rating limits are:
   1. Tag score = 4.5
   2. Block score = 9.8

Confirmation

The emails are no longer detected as Spam false-positives.