Filtering Email Content - Watchguard Firebox X20E User Manual

Configuring the POP3 Proxy

Filtering email content

Certain kinds of content embedded in email can be a security threat to your network. Other kinds of
content can decrease the productivity of your users. On the POP3 Content tab, you limit content types,
and block specified path patterns and URLs. You can use the asterisk (*) as a wild card.
Allow only safe content types
The headers for email messages include a Content Type header to show the MIME type of the email
and the MIME type of any attachments. The content type or MIME type tells the computer the types of
media the message contains. Select the check box for this feature if you want to limit the content types
that you allow through the proxy. When you select this check box, only the content types shown in the
text box are allowed. The format of a MIME type is type/subtype. For example, if you want to allow
JPEG images, you add image/jpg. You can also use the asterisk (*) as a wildcard. To allow any image
format, you add image/* to the list.
To add additional content types to the default list, type the MIME type and click Add.
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To remove a content type, select it from the list and click Remove. You cannot remove
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message/* or multipart/* because the POP3 proxy cannot work without them. If you try to
remove these content types you get an error message.
To add common content types to the list, select the MIME type in the Predefined content type
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column and click the << button.
Deny unsafe file name patterns
If you want to deny certain file name attachments, select the Deny unsafe file name patterns check
box. This is a list of file names or types that you want the proxy to block. Use the asterisk (*) as a wild
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