Configuring attachment filtering

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To configure attachment filtering:

1. Perform the following steps in the Management Console tree:
   • To configure attachment filtering on an unassigned Security Server, select the node of the relevant Security Server.
   • To configure attachment filtering on Security Servers belonging to a profile, expand the Profiles node and select the node of the profile for whose Security Servers you want to configure attachment filtering.
2. Select the Server protection node.
3. In the workspace, select the Protection for the Transport Hub role tab.
4. In the Filtering settings section that opens, define the following settings:
   • Attachment file format

     Filtering of attached files and archives based on file format.

     The application recognizes the format of a file by its structure, that is, by the way it is stored or displayed on the screen. This allows you to filter attachments even if the extension of an attached file does not match the actual type of the file (for example, if the extension has been changed intentionally).

     If this check box is selected, the button is active. Clicking this button opens the File formats window in which you can select file formats. The selected formats are shown in the Attachment file format field.

     The application scans attached and archived files. Upon detection of files of the specified formats, the application applies the action selected in the filtering settings to messages being scanned.

     If this check box is cleared, the application does not filter files by format.

     The check box is cleared by default.

   • Attachment file name

     Filtering of attached files and archives by file name or extension.

     If this check box is selected, the button is active. Clicking this button opens the File name masks window in which you can specify names and / or file name masks manually. You can also import a list of names and / or file name masks in TXT format. The specified names and / or file name masks are displayed in the Attachment file name field.

     The application scans attached and archived files. Upon detection of files that match the filtering criteria, the application applies the action selected in the filtering settings to messages being scanned.

     If this check box is cleared, the application does not filter files by name and / or extension.

     The check box is cleared by default.

   • Attachment size limit (MB)

     Filtering attachments by size of the attachment file.

     If this check box is selected, the spin box on the right is active. In this spin box, you can specify the maximum size of attached files sent in email messages. You can specify a size value from 1 to 999 MB. The default value is 20 MB. If the application detects attachments that exceed the specified size, it applies the action that has been configured in the filtering settings.

     If this check box is cleared, the application does not filter attachment files by format.

     The check box is cleared by default.

   • Action

     Drop-down list in which you can select the action that the application takes on attachments that meet at least one of the filtering criteria:

     • Allow. The application allows sending the email message that contains attachments. This is the default option. To receive information about objects that have been filtered out, you can configure notifications or logging of events in the Windows event log.
     • Delete object. The application removes the object from the attachment or removes the attachment from the email message. The application also adds a file in TXT format to this message; the file contains information about all attachments that have been deleted.
     • Delete message. The application permanently deletes the email message with the attachment that has been filtered out. If you select this option, it is recommended that you save copies of messages in Backup to avoid data losses.
   • Add label to message header

     Adds a tag to the Subject field, which indicates that the attachment was scanned by the application.

     If the check box is selected, the application adds a tag to the message subject. The tag indicates that the message was filtered. The application adds the tag to the Subject field in messages in the following cases:

     • When deleting the attachment
     • When skipping the message

     You can specify the tag text in the entry field on the right. The default tag text is Prohibited Attachment.

     If this check box is cleared, the application adds no tag to the Subject field.

     The check box is cleared by default.

   • Save message copy in Backup

     Saves a copy of the original message in Backup.

     If this check box is selected, the application saves a copy of the message in Backup in the following cases:

     • Before deleting the message
     • Before deleting the attachment
     • When skipping the message

     If this check box is cleared, the application saves no copy of the object in Backup.

     The check box is selected by default.

5. Click the Save button.

The settings that you have specified will be saved. The application filters attachments in accordance with the settings defined. You can toughen the filtering criteria by configuring exclusions from attachment filtering.