User guide

Using VStream Antivirus
Chapter 15: Using Antivirus and Antispam Filtering 523
In this field…
Do this…
• WMA/WMV/ASF
• RealMedia file
• JPEG - only the header is scanned, and the rest of the
file is skipped
To view a list of safe file types, click Show next to this option.
Selecting this option reduces the load on the gateway by skipping
safe file types. This option is selected by default.
Archive File Handling
Maximum Nesting Level Type the maximum number of nested content levels that VStream
Antivirus should scan.
Setting a higher number increases security. Setting a lower
number prevents attackers from overloading the gateway by
sending extremely nested archive files.
The default value is 5 levels.
Maximum Compression
Ratio 1:x
Fill in the field to complete the maximum compression ratio of files
that VStream Antivirus should scan.
For example, to specify a 1:80 maximum compression ratio, type
80.
Setting a higher number allows the scanning of highly compressed
files, but creates a potential for highly compressible files to create
a heavy load on the appliance. Setting a lower number prevents
attackers from overloading the gateway by sending extremely
compressible files.
The default value is 100.