McAfee Security for Microsoft Exchange 8.6.0

Microsoft Virus Scanning API (VSAPI) settings

Microsoft VSAPI allows MSME to scan emails when they are accessed by the end-user using any email client.

In Microsoft Exchange, emails are stored in a database called Exchange Information Store. When a new mail is received, the Exchange server notifies the outlook client about a change. This is when On-access scan is triggered.

This feature is available only on Microsoft Exchange 2007/2010 Server with Mailbox role.
Option definitions
Option Definition
Enable Select to scan email messages only when they are accessed by the end-user using an email client such as Outlook. This feature scans emails that are already available in the Microsoft Exchange Information Store or if there is a mismatch in the AV stamp.
Proactive scanning Select to scan email messages before it is being written to the Microsoft Exchange Information Store.

Enable this feature in these situations:

Where MSME is not configured on the HUB Transport server and if an infected email reaches the Mailbox server, it will be detected before it is being written to the Exchange Information Store.
Usually content posted to a public folder database is usually not routed through a HUB Transport server. In order to ensure that the content is scanned before it gets to the store, it is recommended that you enable proactive scanning for public folder databases.
Outbox Scanning Select to scan email messages in the Outbox folder.

MSME scans the email in the Outbox itself, even before the email reaches the HUB Transport server, thus reducing the load on the HUB server.

Lower Age Limit (seconds) Specify a value, where emails received within the specified duration are only scanned. Emails received before the specified time will not be scanned.

By default, the value is set to 86400 seconds, which is equal to one day.

Scan Timeout (seconds) Maximum time allowed to scan an email. If scanning an email exceeds the specified value, the action specified under Settings & Diagnostics | On-Access Settings | General | On Scan Failure will occur. By default, the value is set to 180 seconds.
Number of Scan Threads Specify the number of pool threads used to process items in the On-access and Proactive scan queue. The default value is 2 * <# of processors> + 1. McAfee recommends that you select the Default checkbox for better performance.