avserver and spamserver are special processes used to maintain applications developed outside Kerio Technologies. These applications include any antivirus plugins (external and/or the built-in McAfee antivirus) and the SpamAssassin antispam filter. As hinted by their names, avserver maintains antivirus plugins, while spamserver maintains the SpamAssassin.

Both processes are represented by executables located in the directory where Kerio MailServer is installed (\Kerio\MailServer\plugins on Windows, /Kerio/mailserver/plugins on Unix-based systems).

The processes were introduced in Kerio MailServer's 6.2 version and they help balance inconsistencies that occurred in connection with the plugins.

Whenever a problem occurs regarding any of the plug-ins (e.g. when connection is closed improperly or if connection “freezes”), automatic restart is initiated by the corresponding process. This implies any error that occurs does not cause failure of the entire mailserver and communication with the corresponding plug-in is even not interrupted for a long time. Initiation of the application's restart also generates and saves a crashdump log that might help discover the problem's cause. Then, when an administrator connects to Kerio MailServer, a Kerio Assist dialog asks them to decide whether the crashdump log would be sent to Kerio Technologies for analysis.