Increasing Exchange Message Size

Note: This article is relevant for Exchange 2007-2016.

This is a two-step process. The reason for this is that if the message size limits of Exchange are increased, the IIS limits will also have to be increased to allow increased payloads. There are other non-standard settings that can also cause size restrictions for the IIS or EWS connections, but we are unable to troubleshoot or identify specific environment restrictions outside of these settings.

Increase the Message Size Limits of Exchange

To display current message size limits:​

  1. Open the Exchange Management Shell.
  2. Enter the following commands:

Get-TransportConfig | Format-List -Property MaxReceiveSize, MaxSendSize
Get-SendConnector | Format-List -Property Identity, MaxMessageSize
Get-ReceiveConnector | Format-List -Property Identity, MaxMessageSize
Get-MailBox | Format-List -Property PrimarySmtpAddress, MaxSendSize, MaxReceiveSize

To increase message size limits on the Exchange Server:​

  1. Open the Exchange Management Shell.
  2. ​Enter the following commands:​

​Set-TransportConfig -MaxReceiveSize 150MB -MaxSendSize 150MB
Get-SendConnector | Set-SendConnector -MaxMessageSize 150MB
Get-ReceiveConnector | Set-ReceiveConnector -MaxMessageSize 150MB
Get-Mailbox | Set-Mailbox -MaxSendSize 150MB -MaxReceiveSize 150MB

 

Increase IIS Limits to Allow Accepting Payloads

Note: There are three limits that should be increased in IIS:

  • maxRequestLength
  • maxAllowedContentLength
  • maxReceivedMessageSize

Follow these steps to increase the Exchange message size limits on your client access server:

  1. OpenWindows Explorer.
  2. Navigate to %ExchangeInstallPath%FrontEnd\HttpProxy\ews\
  3. Open the file Web.Config in a text editor, such as Notepad.
  4. Find the XML tag starting with for each change.
  5. Change the existing value to maxRequestLength="200000"​ -- this occurs in one place in the Web.Config file.
  6. Change the existing values to maxAllowedContentLength="200000000"​ -- this occurs one place in the Web.Config file.
  7. Change the existing values to maxReceivedMessageSize="200000000" -- this entry occurs up to 12 times. This needs to be changed for each Authentication method.
    For example:
    <httpsTransport maxReceivedMessageSize="200000000" authenticationScheme="Anonymous" maxBufferSize="81920" transferMode="Streamed" />
    <httpsTransport maxReceivedMessageSize="200000000" authenticationScheme="Basic" maxBufferSize="81920" transferMode="Streamed" />
    etc.
  8. If you are running IIS7 and Windows 2008, it may be necessary to increase WCF settings.
  9. Save the file.
  10. IIS Reset is not needed, web.config changes are picked up by the next conne​ction.

​​Follow these steps to increase the Exchange message size limits on your mailbox server:

  1. OpenWindows Explorer.
  2. Navigate to %ExchangeInstallPath%ClientAccess\exchweb\ews\
  3. Open the file Web.Config in a text editor, such as Notepad.
  4. Find the XML tag starting with for each change.
  5. Change the existing value to maxRequestLength="200000"​ -- this occurs in one place in the Web.Config file.
  6. Change the existing values to maxAllowedContentLength="200000000"​ -- this occurs one place in the Web.Config file.
  7. Change the existing values to maxReceivedMessageSize="200000000" -- this entry occurs up to 12 times. This needs to be changed for each Authentication method.
  8. If you are running IIS7 and Windows 2008, it may be necessary to increase WCF settings.
  9. Save the file.
  10. IIS Reset is not needed, web.config changes are picked up by the next conne​ction.
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