Microsoft Exchange 2010 – EWS and big attachments

If you need to send big attachments with your MAC clients you need to change the default value for Microsoft Exchange 2010 which is set to 10MB/35MB (First release / SP1)

There are a few steps on how to get this to work, you need to change the file for your entire IIS environment, allowing the RequestFiltering to be changed and then change the actual value for  maxReceivedMessageSize and maxAllowedContentLength.



1. Change your file in “C:WindowsSystem32Inetsrvconfigapplicationhost.config” to allow requestFiltering override to Allow

2. Change your web.config located in “C:Program FilesMicrosoftExchange ServerV14ClientAccessexchwebews” to your new value. If you want to be able to send about 50MB attachments you should change the value to about 85MB as converting to MIME plays a part in this aswell. This value need to be changed on all your bindings that you are going to use, or just change them all to make it easy.

3. And then change your maxAllowedContentLength to the same value as above

4. Run the following command to make it stick after updates (Not sure if this really is needed but It wont hurt)

Start a cmd promt as admin and go to “%windir%system32inetsrv” and then run the following command:


5. Make a restart of your IIS and you should be up and running sending big attachments.


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