The attachment filtering in ORF allows you to filter specific attachment types. The related configuration options are available under in the navigation.
You can enable or disable the use of the Attachment Filtering on the page in the navigation.
Click the Settings button to configure the Attachment Filtering.
Blacklisted attachments can be replaced by a warning message. Edit the warning message text here. Four custom fields are supported by the editor, select these from right-click menu of the text box. The custom fields are replaced by their actual value when an attachment is replaced by the warning text.
Set the SMTP response sent by ORF when an email is dropped due to an attachment filter hit. Click the SMTP Response button to edit the response. More about the SMTP responses is available in the SMTP Responses section of the help.
Blacklisted attachments can be saved by ORF in an arbitrary folder for later retrieval.
ORF quarantines attachments that are replaced by a replacement notice. ORF also quarantines all attachments when the email is dropped by Attachment Filtering (this includes even those attachments which did not match any filter rules).
Attachments are quarantined under their original file name. When this is not possible, ORF generates another file name that closely resembles the original file name. Consult the related ORF log message for the original and the generated file name. A few scenarios when a new file name is generated:
Specify a folder in which quarantined attachments will be stored. The Quarantine Folder path can be localized, see the related help article for more information.
Anti-virus software may prevent ORF from writing a copy of attachment to the Quarantine Folder. In case you want the attachment to be saved even if it possibly contains malicious content, be sure to exclude the Quarantine Folder path from real-time anti-virus checking.
Enable retention to have ORF automatically delete quarantined files older than the configured threshold. Set the threshold using the Automatically delete quarantine contents older than X days option.
Note that retention control is exercised only if the Attachment Quarantine feature is enabled.
Always use a dedicated folder for quarantining purposes. When retention control is enabled, ORF will delete any files in the Quarantine Folder older than the configured threshold, even if they were not placed there by ORF.
Click the New button to add a new attachment filter to the list. To modify an existing attachment filter, click Modify or hit Enter. Attachment filters can be deleted using the Delete button or the Delete key.
Click the column header of any column by which you wish to sort the attachment filter list. To reverse sorting, click the column header again.
Right-click on the expression list and select "Import List..." or "Export List..." Alternatively, you can do this from the menu, select or .
Attachments can be filtered based on the attachment file name or the attachment MIME type or both (combined).
Set the Filter by attachment name checkbox to filter by the attachment name. This can be combined with the content type filter on the MIME Content Type tab.
Select the filter type (can be a simple text file name / wildcard expression or a regular expression) and enter the desired file name or expression to the Attachment Name edit box.
Set the Filter by MIME content type checkbox to filter by the attachment's content type. This can be combined with the attachment file name filter on the Attachment Name tab.
Select the filter type (can be a simple text / wildcard expression or a regular expression) and enter the desired MIME type name (e.g., image/jpeg) or expression to the Content type/regular expression edit box.
Test your expression using the Test attachment name and Test content type edit boxes. If the test box contents match with the mask, a green "Match" label appears on the right side of the test box.
Select the action to be performed when the attachment is blacklisted by the filter. You can choose to replace the attachment with a removal notice or to drop the entire email.
Add an optional comment to the filter expression. This comment is logged when the filter expression catches an attachment. Helpful when you have to know which expression caught the email. The comment also can be used in the warning message text.
The attachment filtering can be used at the On Arrival filtering point only. Before email arrival, the email contents are not available, so the attachment filtering cannot be performed at that point.
By using regular expressions, you can easily filter attachments by file name extensions.
Filtering UUENCODED attachments are not supported. See the Limitations section for more information.
ORF cannot scan files inside archive files (i.e., if you block EXE files, ORF will allow them through if they are inside a ZIP files). See the Limitations section for more information.