Tuesday, July 31, 2012

Exchange 2010 Client Throttling Policies

Exchange 2007 introduced a feature called RPC Client Throttling to allow administrators to manage end-user performance by preventing client applications, such as Outlook for example, from sending too many Remote Procedure Call [RPC] requests per second to Exchange, causing the server to suffer in terms of performance. When Exchange determines that a client is having a negative effect on the server, it will send a "back-off" request to the client telling it to delay sending any additional requests for a specified time (maximum of 2000 milliseconds) in order to reduce the performance effect on the server.

In Exchange 2010, Client Throttling has been much improved, monitoring and controlling much more than just RPC requests. Its purpose is still to ensure that users are not intentionally or unintentionally straining Exchange and that users share resources proportionally.

In this article, we will explore Client Throttling Policies in Exchange 2010, what they are used for and how to change them if necessary.

For the full article, please click here: MSExchange.org.


  1. In working with Microsoft Professional Services to allow a user to open more than 250 e-mails, I came across your article, as MSFT was configuring these policies in an attempt to resolve this issue. This did not resolve the issue. Do you know how to set Exchange to allow Outlook to open 250 messages at the same time?

    1. Hi,

      Unfortunately I do not know... But may I ask why you need to open more than 250 e-mails? Maybe we can find a different approach/solution.

      Regards, Nuno