Mailguard - How to block Microsoft Office macros

Are you receiving unwanted e-mails that contain Microsoft Office files with macros? As you may know, these macros can do virtually anything that any other executable file can. Given this, the potential for malicious content is extremely high and blocking these files is strongly recommended. But, this feature is optional because there are still many people that exchange legitimate files containing macros.

If you would like to enable this protection, please contact us and request that we enable the OFFICE_MACRO rule-set for your account.

We Answer Your Questions: FAQ

Q: What is the maximum e-mail attachment size?

A: The e-mail servers do not limit the size of individual e-mail attachments. The e-mail servers do impose a 400 MB maximum total message size limit. Individual customers can choose a smaller message size limit. We can also customize the handling of "over-sized" e-mails. Please contact us to discuss your specific needs. A couple of important facts:

1. Attachments are typically encoded in what is called Base64[1]. As a result, the actual length of MIME-compliant Base64-encoded binary data is usually about 137% of the original file size.

2. E-mails often contain both plain text and HTML components. This also increases the overall size of the e-mail.