The Reply-all Storm Protection feature in Exchange Online helps protect your organization from unwanted and disruptive reply-all storms. Last year we updated the feature to give admins the ability to...
Updated Apr 23, 2022
Version 2.0
Blog Post
Exchange Team Blog
2 MIN READ
New Reply-all Storm Protection Report, Settings UI, and Alert Policy
The_Exchange_Team
Apr 22, 2022Platinum Contributor
KevinShaughnessy
Microsoft
Apr 30, 2022MicrosoftExchSupport-SA RE allowing changing minimum recipients threshold to 250: Thanks for your feedback! We'd love to. However, the current possible minimum setting of 1000 was chosen for a number of reasons. The most important of which is that it reduces the risk of erroneously identifying a legitimate conversation as a reply-all storm. Our analysis suggests that most legitimate conversations take place on DLs with 500 or fewer recipients/members. Enabling the feature for threads with 500 or fewer recipients would significantly raise the likelihood of blocking legitimate conversations, so its value in blocking actual reply-all storms would be cancelled out by a preponderance of false positive detections. A lot of customers would probably get annoyed/upset about the false positives, then either disable the feature entirely or raise the threshold to a higher value (like 1000) to reduce those false positives and their impact on legitimate business communications - both of which would make it moot for organizations with fewer than 1000 users anyway.
We do understand that organizations with less than 1000 users also suffer from reply-all storms, and we'd like to expand the feature's protection to those customers as well, so long as we can do it in a way that minimizes the chance of false detections. It won't be any time soon, but I believe it's something we'll be able to do in the future. Thanks again for your feedback!