How does Large File Send work?

Document created by user.oxriBaJeN4 Employee on Sep 7, 2015
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Large File Send enables users to send and receive files up to 2GB through an upload from Mimecast for Outlook directly to the Mimecast service. This feature is also available in Mimecast for Mac.


Note: the ability to receive files through the Large File Send service requires use of either Large File Send Prime or Large File Send Pro.


These attachments bypass the organization's email server, and are not governed by attachment size limits and therefore do not take up storage on the email server.  Attachments are scanned by Mimecast for malware, and may be passed through attachment rules using the Attachment Management Policies and Content Definitions, depending on your commercial package. The recipient then receives a notification which is made up of the original message and a link to download the attachments from the Large File Send portal.


How it works

The sender composes an email with Mimecast for Outlook or Mimecast for Mac. When the message is sent, the attachments are silently uploaded through an encrypted channel to the Mimecast Large File Sendportal.  At this stage, the email is passed through the Policies as described above if configured by the Administrator, and the original email is stored in the Archive for the retention period of the Mimecast account.


Once an appropriate file is attached to an email, and Large File Send is activated, the file is cached locally on the workstation and is transmitted to Mimecast.  Once the file has been transmitted, the cached copy is removed.  During the upload process, the file is transferred in chunks.  If the uploads are paused and resumed at a later stage, the partial transmission can be resumed from where it left off.  If the transfer is interrupted due to connectivity issues, an auto-resume process will activate once connectivity has been restored.


Securely sending large files via email is a real problem, and has become a battle between users and IT departments.  Seeking to protect overall email system performance, IT teams routinely set limits on email size – file sizes in general are growing, so users often struggle to share vital content with internal and external contacts. The availability of the file sent with Large File Send is also controllable, and users can expire links at any time.


Next steps

To use Large File Send to send large email attachments view the following article: