Posteli raises your Office 365 or on-prem Exchange Server message size limits and leverages Exchange Server’s Smart Host feature by sending all outbound email to Posteli’s email processing servers. We strip the large attachments and upload them to our secure servers. The recipients still receive the sender’s message but with links to the attachments instead of the attachments themselves.

This way, Office 365 users can send 150 MB messages, and users at Hotmail, Gmail, etc. will receive your message.