You can restrict HTTP network traffic and POP3, IMAP, or SMTP email attachments by content type. You can use the Content Type categories of these proxy actions to allow or deny the content types you specify.
- In the proxy action, select Content Types.
- Click Predefined.
The Select Content Type dialog box appears.
- Select one or more common content types to add to the Content Types list.
Use the Control and/or Shift keys to select multiple content types at the same time.
- Click OK.
The selected content types appear in the Content Types list.