This article describes the licensing definitions for Barracuda email protection products.
Barracuda Email Protection Plans
Barracuda Networks requires the same number of licenses as the number of mailboxes that have an Exchange license in the organization's Office 365 account.
Standalone Products and Legacy Bundles
For customers using Office 365 and Impersonation Protection (formerly Barracuda Sentinel) and/or Incident Response (formerly Barracuda Forensics)
Barracuda Networks requires the same number of licenses as the number of mailboxes that have an Exchange license in the organization's Office 365 account. This mailbox count for Impersonation Protection or Incident Response will be used for all Barracuda SaaS products.
For customers not using Impersonation Protection (formerly Barracuda Sentinel) or Incident Response (formerly Barracuda Forensics)
Barracuda Networks requires the same number of licenses as the organization's monthly active recipients. This count includes all email addresses that are receiving emails, along with users whose email is being archived. Email aliases, distribution lists, and invalid recipients are excluded from this count, as long as they are marked as such within the Barracuda Networks product.
Shared Mailboxes
Microsoft requires a license for shared mailboxes larger than 50GB. As such, Barracuda Networks also requires a license for any shared mailboxes over 50GB.