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Loadbalancer.org provide an exceptional product that supports our Exchange Cloud platform of in excess of 100,000+ mailboxes and services. As we have grown we have had every confidence that the products provided are capably of supporting our needs. Without doubt with a great product comes exceptional support. The support team are fast, friendly, know the product and always go the extra mile to help. We will always recommend this company, products and its support staff and they can only be classed as 5*. Thank you.

Mark Ellam

Giacom World Networks

Load Balancing Microsoft Exchange

Now, more than ever, your organization requires cost-effective and flexible communication tools. With Microsoft Exchange Server you can achieve new levels of scalability and performance with features that simplify your administration, help protect your communications, and delight your users by meeting their demands for greater mobility.

Microsoft Exchange Server, the cornerstone of Microsoft’s Unified Communications solution, is a flexible and reliable messaging platform that can help you increase productivity with anywhere access to business communications, and safeguard your business with protection and compliance capabilities that help you manage risk.


When deploying Microsoft Exchange Server for high traffic throughput, organizations must look to implement a scalable solution. To scale the deployment of the Microsoft Exchange Server, Microsoft recommends using a hardware load balancer to distribute the traffic among multiple Exchange servers.

There are a number of ways to configure the load balancer for Exchange. For Exchange 2010 we typically recommend using 4 VIPs (HTTP/HTTPS, RPC, IMAP/POP3 & SMTP). For Exchange 2013 and Exchange 2016 we typically recommend using 3 VIPs (HTTP/HTTPS, IMAP/POP3 & SMTP). These configurations are simple to setup but still ensure granular control and health checking of the various Exchange services.

For Exchange 2010 we recommend layer 7 SNAT mode to allow for various persistence (affinity) options. Exchange 2013 & 2016 no longer require persistence so layer 4 (either Direct Server Return mode or NAT mode) is recommended.

The improvements in Exchange 2013 & 2016 make the deployment of a scalable high-availability email cluster a more straight-forward task. Further discussion can be found in this blog post.

Useful Links:

Microsoft approved load balancers for Exchange
Load balancing Exchange case study
MSExchange.org product review

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