Maximum Email Size

For safety reasons, our filters apply limitations on the sizes of emails and the contents of zipped archives that are allowed on our network.

This article applies to Administrator accounts - Quarantine Administrator accounts can view this information but cannot edit the parameters.

Email Size

The maximum size for a single email is configurable and is set to 50 MB by default. This can be adjusted to less than 50 MB to be in-line with your email server's configuration. Email size takes into consideration headers, body content and attached files encoded in base64 (which typically inflates files by 33%). If a message exceeds the 50 MB limit, it will be rejected and a DSN will be returned to the sender. 

At this time, there is no way to increase the maximum-allowed email size to more than 50 MB.

Zip Files

Large attachments should be sent by other means such as using the FTP protocol or a web file transfer service such as Dropbox, Google Drive, or OneDrive.

While sending of zipped documents is permitted, we impose two limits for security reasons:

  1. The unzipped file may not be larger than 250MB.
  2. The unzipped file may not have more than 48 levels.

Messages going over these limits will be treated the same as Banned Files (see Related Articles) and a special DSN message explaining the situation will be sent.