Configuring Attachment Blocking

Configuring attachment blocking options for Microsoft Exchange servers involves setting the rules to block messages with certain attachments.

For Real-time Scan:

Security Settings > {Messaging Security Agent} > Configure Settings > Attachment Blocking
For Manual Scan:

Scans > Manual > {Expand Messaging Security Agent} > Attachment Blocking
For Scheduled Scan:

Scans > Scheduled > {Expand Messaging Security Agent} > Attachment Blocking

From the Target tab, update the following as required:
- All attachments: The agent can block all email messages that contain attachments. However, this type of scan requires a lot of processing. Refine this type of scan by selecting attachment types or names to exclude.
  - Attachment types to exclude
  - Attachment names to exclude
- Specific attachments: When you select this type of scan, the agent only scans for email messages containing attachments that you identify. This type of scan can be very exclusive and is ideal for detecting email messages containing attachments that you suspect contain threats. This scan runs very quickly when you specify a relatively small amount of attachment names or types.
  - Attachment types: The agent examines the file header rather than the file name to ascertain the actual file type.
  - Attachment names: By default, the agent examines the file header rather than the file name to ascertain the actual file type. When you set Attachment Blocking to scan for specific names, the agent will detect attachment types according to their name.
- Block attachment types or names within ZIP files
Click the Action tab to set the actions that the Messaging Security Agent takes when it detects attachments. The Messaging Security Agent can perform the following actions (For descriptions, see Scan Targets and Actions for Messaging Security Agents):
- Replace with text/file
- Quarantine entire message
- Quarantine message part
- Delete entire message
Select Notify recipients to set the Messaging Security Agent to notify the intended recipients of email messages that have attachments.
Select Do not notify external recipients to only send notifications to internal mail recipients. Define internal addresses from Operations > Notification Settings > Internal Mail Definition.
Select Notify senders to set the Messaging Security Agent to notify the senders of email messages that have attachments.
Select Do not notify external senders to only send notifications to internal mail senders. Define internal addresses from Operations > Notification Settings > Internal Mail Definition.
Click the plus (+) icon to expand the Replacement Settings subsection.
1. In the Replacement file name field, type the name of the file that Attachment Blocking will replace an email message with when a rule using the “Replace with text/file” action is triggered, or accept the default value.
2. In the Replacement text field, type or paste the content of the replacement text for Attachment Blocking to use when an email message triggers a rule whose action is “Replace with text/file” or accept the default text.
Click Save.