Media streams can be scanned on Web Gateway chunk-by-chunk, which allows users to see or hear downloaded streaming media faster, as they do not have to wait until a stream has been scanned completely.
This scanning method is performed by the Media Stream Scanner, which is provided by the Gateway Anti-Malware engine. Streaming media is scanned and delivered chunk-by-chunk to the client that requested the download. If an infection is detected in a chunk, the download stops, and this chunk and the rest of the streaming media are not delivered.
The scanning that is performed by the Media Stream Scanner uses the proactive functions of the Gateway Anti-Malware engine. The Avira engine, which can also be configured to scan web objects for infections by viruses and other malware, is not involved when the Media Stream Scanner is active.
The scanner is started by an event of a rule in the Gateway Anti-Malware rule set of the default rule set system. The rule applies if the Stream Detector module finds that a web object that was received on Web Gateway in response to a download request is streaming media.
Processing of the rule set stops and the remaining rule in the rule set, which also lets web objects be scanned for infections by viruses and other malware, is not processed.
If a web object is not recognized by the Stream Detector as streaming media, the rule does not apply, processing continues with the remaining rule, and the web object is scanned according to the settings that are configured for this rule.