Google Message Security for Google Apps Administration Guide - Manual (Page 278)

278 Message Security for Google Apps Administration Guide
5. Enter file types in the Custom File filters. These filter are most useful if you’re
filtering only a few types of files. See “Custom File Types Filter” on page 281
for details.
6. Set up filters for broad categories of files using the System Threats and
Productivity filters. See “System Threats and Productivity Filters” on page 281
for details.
7. Optional: Configure binary scanning as the method to identify file types. See
“Troubleshoot Attachment Manager” on page 282 for details.
8. If you haven’t done so already, configure notifications for messages that
trigger Attachment Manager filters. By default, notifications are automatically
sent to the administrator only, but can be sent to the user or both the user and
administrator. See “Configuring Notifications for an Organization” on
page 149 for information on setting up notifications.
Tip: You can allow Approved Senders for an organization to bypass all
Attachment Manager filters by clicking the Approved Senders check box on
the Attachment Manager configuration page. See “Configure Attachment
Manager” on page 275 for more information.
Attachment Filter Order
In Attachment Manager, filters are evaluated in the following order. The
disposition of the first filter triggered is performed:
1. Message Size: First, attachments are evaluated for size. If a message
triggers this filter, the message is bounced, regardless of whether the
attachment is approved by any subsequent attachment filter.
2. Custom File Types: These are any file types you've specified to approve,
bounce, or quarantine, as exceptions to subsequent filters. These filters are
applied before other file type filters. So if you approve .gifs here, but
quarantine image files using the Productivity filter, .gifs are approved, while
other images are quarantined.
3. System Threats: Next, this filter approves, bounces, or quarantines a
collection of compressed and executable file formats, including
.exe , .zip ,
.tar , and many others, as well as attachments with multiple file extensions,
such as .tar.gz .
4. Productivity: Lastly, this filter approves, bounces, or quarantines a collection
of common document, image, multimedia, and spreadsheet file types.
Attachment Filter Dispositions
Each attachment filter can have a different disposition, depending on your
particular policies (except the message size filter, which always bounces
offending messages). You might want to bounce dangerous executables, for
example, but merely quarantine images or sound files.