Rules written against attachment names or extensions via the "attachment or body part" policy condition fail to detect matching files within winmail.dat attachments.
For example, a content filtering rule is written to detect file attachments with the .png extension will detect PNG files attached to plain text and HTML encoded email messages but does not detect PNG files enclosed within Microsoft Rich Text formatted emails.
Messaging Gateway "attachment name" rules were not run against TNEF encoded objects. This primarily affected winmail.dat attachments used in Microsoft rich text formatted emails.
This issue has been addressed with the SMG 10.6.2 release.
Messaging Gateway will now test attachment name rules against all named parts of a TNEF encoded / Microsoft Rich Text attachment.