Knowledge Base

Exchange Rules Service (Engine) overload during high traffic periods


You have noticed some unusual software behavior or server performance issues that present themselves only when CodeTwo Exchange Rules Pro 2 or CodeTwo Exchange Rules is enabled. For example, CodeTwo software utilizes rather big chunk of the CPU power, some emails are processed improperly or seem to be processed partially only (e.g. signatures are added but without AD placeholders).


Starting version 2.1.0 the software has a built in solution to the Agent timeout problem which is modification of number of maximum connections for communication between CodeTwo agent of MS Exchange Transport service and Exchange Rules Service (this number is now 100). This fixed one issue but potentially generates other type of problems that may emerge in low performance environments that experience big emails traffic. If that happened to you, you probably already contacted CodeTwo Customer Support which directed you to this article. If this is not the case CodeTwo strongly advises against applying the below solutions without CodeTwo technicians analysis of the problem.

To fix the CodeTwo Exchange Rules Service performance issues you need to tweak the below settings values:

  1. maxConnections value of netNamedPipeBinding property in CodeTwo.ER.Engine.Service.exe.config file. Starting version 2.1.0 of CodeTwo Exchange Rules Pro this value by default is 100. Previously it used to be just 10. You may need to experiment with this setting looking for optimal value in the range between 10 and 100. You can start with just 10 and observe server performance. If you find any messages unprocessed you can either increase this value or work with Agent timeout settings described below. Please consult with this article on how to modify the Exchange Rules Service config file.
  2. Timeout settings in Agent.xml file. By default the timeout values are 30000ms. You will have to extend those considerably (e.g. to 50 000ms) to allow more time for Agent queuing if the maxConnection value of the Exchange Rules Service cannot be increased any more in your environment. Please consult with this article on how to modify the Agent config file.

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