Trend Micro InterScan M Series, Administrator'S Manual

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Trend Micro™ InterScan™ Gateway Security Appliance M-Series Administrator’s Guide
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Deferred Scan
Deferred scan ensures that the connection between the client and InterScan Gateway
Security Appliance remains open while large file scanning takes place. A client
requests a file from an FTP or HTTP server, and the server sends the file to the client
located behind the appliance. The appliance receives the file and starts scanning it.
However, if the file is large it can take the appliance some time to complete the scan.
If the time it takes to scan the file is too long, the connection between the client and
the appliance will be lost, and the client will not receive the file.
To ensure that the connection with the client remains open while file scanning occurs,
the appliance sends packets to the client one by one. The packets are sent to a
temporary folder on the client. If the appliance detects a threat, it immediately stops
sending packets, and a notification appears on the user’s browser. The user sees a
folder on the local computer with a partial file in it. Because the file is incomplete, it
presents no danger.
Diskless Mode
InterScan Gateway Security Appliance can operate in diskless mode when there is a
problem with the device hard disk. InterScan Gateway Security Appliance uses the
disk SMART system test feature to determine is there is a problem with the device
hard disk. If disk SMART Test detects a problem, InterScan Gateway Security
Appliance will reboot and begin operating in diskless mode.
• When InterScan Gateway Security Appliance is in diskless mode, the following
features are disabled:
• Manual and Scheduled Update —InterScan Gateway Security Appliance will
not download updates
• Logging —InterScan Gateway Security Appliance will not log events
• Quarantining —InterScan Gateway Security Appliance will not quarantine
specified items
• World Virus Tracking Program —InterScan Gateway Security Appliance will
not track virus information for the World Virus Tracking Program
Another effect of diskless mode is a reduction in InterScan Gateway Security
Appliance scanning capability. InterScan Gateway Security Appliance is usually
capable of scanning four items concurrently, but when in diskless mode, it can only