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Difference between Transport Scan and On-Access Scan


Article ID: 161857


Updated On:


Mail Security for Microsoft Exchange


You want to know the difference between "Transport Scan" and "On-Access Scan" in Symantec Mail Security for Microsoft Exchange (SMSMSE). 


Transport scan is scanning the emails which are in transit (SMTP transport pipeline). When user sends any email it goes to Exchange HUB transport for further routing, and before user receives any email it comes through Exchange HUB transport. SMSMSE has Exchange transport agent sitting in Exchange transport to get the messages for scanning before it reaches to mailbox.

On-Access: When email reach to user mailboxes and user access that message (Launch Outlook and open email), the emails gets submitted for scanning. Here SMSMSE uses Microsoft Exchange’s VSAPI to get the messages for scanning when they are accessed. VSAPI is available only till Exchange 2010, it has been deprecated in Exchange 2013, i.e. On-Access scanning is not supported in Exchange 2013

Mailbox migration is not considered as either one of the above. There is no virus detection during mailbox migration.

Applies To


Exchange 2013