Symantec Security 5600 Series, Security 5400 Series,Clientless VPN 4400 Series, Administration Manual

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304 Controlling traffic at the security gateway
Blocking inappropriate content with content filtering
Related information
For further information related to this topic, see the following:
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“Content Filtering—Advanced Restrictions tab” on page 646
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“Content Filtering Advanced Restrictions tab—MIME Type dialog box” on page 648
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“Adding content filtering protection to a rule” on page 316
Filtering by file extension
You can create an allow or deny list (but not both) to control access to files with certain extensions for
HTTP traffic. This provides a way to allow or deny specific file types. For example, you can allow users
to download text or HTML files, but not binary executables. This feature is enabled when you check
Apply file extension restriction in the HTTP parameters for a rule that contains HTTP.
Files with no extension are assumed by default to have .html extensions.
Prerequisites
None.
Filter by file extension
To fIlter traffic based on a specific file extension, you must do the following:
■
Specify the file extension and whether it is allowed or denied.
■
Create a rule and apply the file extension restriction.
To filter by file extension
1 In the SGMI, in the left pane, under Policy, click Content Filtering .
2 In the right pane, on the Advance Restrictions tab, under File Extensions, in the Available list,
select the file extension you want to restrict and click the right-arrow > button to add it to the
Selected list.
3 To remove a file extension from the Selected list, highlight the entry, and then click the left-arrow <
button.
The entry is moved to the Available list.
4 To add new file extensions to the Available list, do the following:
■
Under the File Extensions Available list, click Add .
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In the File Extension dialog box, in the File extension text box, type the file extension that you
want to add.
■
Click OK .
5
On the Advanced Restrictions tab, to delete a file extension from the Available list, highlight the
entry, and then click
Delete .
6 To allow or deny the file extensions in the Selected list, below the list, select one of the following:
7
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 .
Allow Permits users to download only files with the file extensions in the Selected list.
Deny Permits users to download all files regardless of extension except those in the Selected list.