Office 365 receives protection against Reply-All email storms

This week, Microsoft is rolling out an important Office 365 update that was designed to protect against Reply-All email storms.

The problematic situation occurs when an employee uses the function for mass emailing, thus generating a massive amount of traffic that has the potential to bring down an email server.

Since the chances of this happening are fairly high, Microsoft decided to address the issue.

At Microsoft, there were two noteworthy accidents related to this, both of which ended up clogging the in-house communications for hours – the first dated back to January 2019 and the second took place in March 2020.

Microsoft announced that it would patch the Office 365 Exchange email server issue at last year’s Ignite conference, and the feature will be rolling out this week.

Once it goes live, email threads that include more than 5,000 recipients will be blocked.

Generating in excess of 10 Reply-All sequences within the last 60 minutes is another red flag that triggers the filter.

Upon detection, Exchange Online will block every single email reply for the course of the next four hours.

This will help email servers to prioritise the emails that are actually important.

In the future, additional updates are expected.

One of these will give administrators the ability to set their own storm detection limits.

Going forward, Microsoft promises to introduce additional reporting and real-time notification features, the latter of which will help administrators to keep a watchful eye on their email servers and prevent an email storm from causing slowdowns or crashes.

Given the fact that Microsoft has had the opportunity to test the new feature internally, this should prove to be a sturdy fix.

According to the Exchange team, such behaviour is human, so it is to be expected.

The first version of the new email storm protection is showing promising results within Microsoft already.