Slow SMTP Connections to SmarterMail

This article applies to recent versions of SmarterMail. View articles for SmarterMail 15.x and earlier.

If you are experiencing slow incoming SMTP connections to SmarterMail and the server uses a multi-core processor, we recommend changing the mode that the .NET Garbage Collector runs in to "Server mode". What this does is provide each CPU on the server, with its own object heap and garbage collection thread so, it can run the process in parallel. This should significantly speed up SMTP processing.

In order to implement this change do the following:

  1. In Notepad, create a file called MailService.exe.config in the same folder as MailService.exe. By default, this folder is located at C:\Program Files (x86)\SmarterTools\SmarterMail\Service.)
  2. Paste the following configuration (remove spaces from opening chevrons):
<?xml version="1.0"?>
<gcServer enabled="true"/>
<loadFromRemoteSources enabled="true">< /loadFromRemoteSources>
<customErrors mode="Off">< /customErrors>
<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
  1. Save the file.
  2. Stop and restart the SmarterMail service.
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I`m using the 11.6 version and the connection get slow after "MAIL FROM:" statement. The .config file has been already with the code above and it is still slow.
Allan Zeidler (11/12/2013 at 6:56 AM)
Allan, this is one way to optimize a multi-core server, but there could be another issue causing slow SMTP sessions on your server. Best bet is to contact our technical support staff or try posting in our forums.
Derek Curtis (11/12/2013 at 8:29 AM)