An e-mail message that is supposed to have an attachment arrives without it and it looks like the attachment is getting stripped. At first glance, it appears that the Symantec Messaging Gateway appliance may be doing it. However, when searching Message Audit Logs (MAL) to see what happened to the message, the message details are showing the verdict as 'none' and the delivery field shows the IP address of the downstream mail server. Furthermore, it also reports that there was an original attachment in the message.
The information provided by the MAL indicates that the Symantec Messaging Gateway appliance did not strip the attachment. "Verdict: None" implies that the message did not trigger any policies or filters when it was scanned. Also, the information shown in the "Deliver to:" field implies that the message was handed off successfully to a downstream server.
Therefore, because no policy was triggered, the SMG did not strip the file. It is possible that another application, such as an e-mail client (such as Microsoft Outlook) or an antivirus program is stripping the attachment. It is recommended to check the security and other related settings of such applications and adjust settings as needed to allow attachments to go through.