Symantec Security 5600 Series, Security 5400 Series,Clientless VPN 4400 Series, Руководство администратора

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338 Preventing attacks
Protecting your network resources from virus infections
Blocking mail that exceeds a maximum size
You can filter mail based on the file size by specifying a maximum size for messages. The maximum
size includes the message and all attachments. Messages that exceed the maximum size are rejected.
Prerequisites
None.
To block mail that exceeds a maximum size
1
In the SGMI, in the left pane, under Policy, click Antivirus .
2 In the right pane, on the Configuration tab, on the SMTP subtab, check Block emails that exceed
the maximum size .
3 In the text box, type the maximum size (in bytes).
4 Optionally, do one of the following:
■
To save your configuration now and activate later, on the toolbar, click Save .
■
To activate your configuration now, on the toolbar, click Activate .
When prompted to save your changes, click Yes .
5 To apply this setting, create a rule and enable the appropriate action on the Antivirus tab.
Related information
For further information related to this topic, see the following:
■
“Antivirus—Configuration tab” on page 630
■
“Antivirus Configuration tab—Add File Extension dialog box” on page 633
■
“Adding antivirus protection to a rule” on page 347
Specifying file types to scan
The security gateway lets you control the types of files that are scanned. You can specify file extensions
that you do not want to scan, and you can omit the scanning of files that do not have file extensions.
You can also scan all file types regardless of extension. Scanning all files regardless of extension is the
most secure setting but could impose a demand on resources.
Note: During virus outbreaks, you might want to scan all files even if you normally control the file
types that are scanned with the inclusion list.
The security gateway scans all files except those that are listed in the exclusion list. The default
exclusion list contains those file types that typically are unlikely to contain viruses, but you can edit
this list. The security gateway ignores the file extensions exclusion list when you have activated the
setting to scan all files regardless of extension.
Prerequisites
None.
Specify file types to scan
The security gateway lets you configure the following scanning options:
■
Scan all files regardless of extension
■
Scan files except those with extensions in the exclusion list
■
Omit the scanning of files that do not have extensions