Unpatched or Unsupported Microsoft Exchange Servers Can Expect an SMTP 450 Error

On Monday, March 24th, 2023, Microsoft announced that it is enabling a transport-based enforcement system in Exchange Online serving three functions: reporting, throttling, and blocking.

For the sake of security, Microsoft is enforcing Zero Trust model upon its Exchange on-premises users that are running unsupported or unpatched servers, making it impossible for bad actors to infiltrate unprotected networks, because emails will fail to go through.

What does this mean?

• By not allowing on-premises exchange mail flow to Exchange Online for unpatched/unsupported versions, end-users will receive an SMTP 450 Error.

When does this take effect?

• In an effort to allow users to prepare, Microsoft will be rolling this plan out in short phases of 30, 60, and 90 days. Microsoft will begin with a small subset of outdated servers, Exchange 2007 servers.

What next?

In order to maintain business continuity, contact Cornerstone.IT immediately to discuss your options.

If you are a small or mid-sized law firm IT leader, the strain of security vulnerabilities, patching, and upgrades, put on your team, is preventing them from focusing on moving your firm forward in the competitive legal landscape.  With over 20 years of experience partnering with law firms Cornerstone has become a trusted and reliable Professional IT and Managed Services resource to law firms across the nation.

Let us help you get back to your business, contact us today!

More reading:

• https://cornerstone.it/ManagedServices
• https://techcommunity.microsoft.com/t5/exchange-team-blog/throttling-and-blocking-email-from-persistently-vulnerable/ba-p/3762078