DKIM Signing Agent for Exchange Server.

This code is mainly based on the work of http://nicholas.piasecki.name/blog/2010/12/dkim-signing-outbound-messages-in-exchange-server-2007/

WARNING: Please read the 'Known Bugs' section before you continue!

This Transport Agent is fully tested under Exchange 2010 SP3 with Windows Server 2008 R2.

If it's running on other version not mentioned here, please notify me, so I can update it here.

Exchange 2010 SP2 doesn't seem to be supported. See Issue #5. If you have SP2 installed, please read Issue #5 and send me the requested files so that I can recompile it for SP2, then it should work.

1. Copy thw whole content from the release directory into a directory on the server, where Exchange runs. Eg. into C:\Program Files\Exchange DKIM\

2. Create the registry key for EventLog by executing the script: [Create Key.reg](Utils/Create key.reg?raw=true)

3. Then open Exchange Management Shell

	Install-TransportAgent -Name "Exchange DKIM" -TransportAgentFactory "Exchange.DkimSigner.DkimSigningRoutingAgentFactory" -AssemblyPath "C:\Program Files\Exchange DKIM\Exchange.DkimSigner.dll"
	 
	Enable-TransportAgent -Identity "Exchange DKIM"
	Restart-Service MSExchangeTransport

4. Close the Exchange Management Shell Window
5. Check EventLog for errors or warnings

Edit the .config file to fit your needs.

<domainInfo>
  <domain Domain="example.com" Selector="sel2012" PrivateKeyFile="keys/example.com.private"/>
  <domain Domain="example.org" Selector="sel2013" PrivateKeyFile="keys/example.org.private"/>
</domainInfo>

You can add as many domain items as you need. For each domain item, the domain, the selector and the path to the private key file is needed. This path may be relative (based on the location of the .dll) or absolute.

The dkim signing agent logs by default all errors and warnings into EventLog. You can set the LogLevel in the .config file:

<setting name="LogLevel" serializeAs="String">
  <value>2</value>
</setting> 

Possible values: 0 = no logging 1 = Error only 2 = Warn+Error 3 = Info+Warn+Error

You can use the following service for creating public and private keys: http://www.port25.com/support/domainkeysdkim-wizard/

Or if you have a linux installation, use (from the opendkim package): opendkim-genkey -D target_directory/ -d example.com -s sel2012

If you want to test, if everything is working, simply send a mail to check-auth@verifier.port25.com and you will get an immediate response with the results of the DKIM check.

If you want to update the Exchange DKIM Transport Agent, you need to do the following:

• Open Powershell and stop the services, which block the .dll

    StopService MSExchangeTransport
  

• Then download Exchange.DkimSigner.dll and overwrite the existing .dll

• Start the services again

    StartService MSExchangeTransport
  

• [unconfirmed] When using internal Receive Connectors as Relay, unicode characters may break and will be replaced with '?'. See: Issue #2

It isn't allowed to distribute the .dll required for development of this transport agent. http://blogs.msdn.com/b/webdav_101/archive/2009/04/02/don-t-redistribute-product-dlls-unless-you-know-its-safe-and-legal-to-do-so.aspx

Therefore you have to copy all files from

C:\Program Files\Microsoft\Exchange Server\V14\Public
Microsoft.Exchange.Data.Common.dll
Microsoft.Exchange.Data.Common.xml
Microsoft.Exchange.Data.Transport.dll
Microsoft.Exchange.Data.Transport.xml

into the Lib directory of this project.

• 24.02.2013: Added multi domain support

• Allow use of relaxed or any combination between relaxed and simple