Microsoft adds protection against Reply-to-all email storms to Office 365

"Reply-to-all storms can disrupt business continuity and in some cases even cripple your organisation's entire email environment for a period of time. At Microsoft Ignite 2019, Microsoft announced the "Reply All Storm" protection feature to reduce the impact that all email storms can have on large organisations.
On Thursday, it was announced that Microsoft is now rolling out this feature globally in Office 365. From 10 replies to anyone on a scale of 5000 within the hour (60 minutes) you will get the message below.

EOP - Exchange Online Protection
Exchange Online Protection (EOP) is the cloud-based filtering service that helps protect your organisation from spam and malware. EOP is included in all Microsoft 365 organisations with Exchange Online mailboxes.
EOP is available in the following 2 scenarios:
- In a standalone scenario: EOP provides cloud-based email security for your on-premises Exchange organisation or for any other on-premises SMTP email solution.
- In a hybrid deployment: EOP can be configured to protect your email environment and control email routing when you have a mix of on-premises and cloud mailboxes.
In these scenarios, EOP can simplify the management of your email environment and alleviate much of the burden associated with maintaining on-premises hardware and software. The rest of this topic explains how EOP works in standalone and hybrid environments.

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