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I have an SMTP Event Sink to process incoming SMTP email messages to perform special processing. Under IIS 6/SMTP, this event sink runs as expected. Under IIS 7/SMTP, it does not appear to run, even though it appears to register successfully, as shown below:

c:\Program Files\Kryptiq Corporation\GW\Bin>regsvr32 SpoolFilter.dll

c:\Program Files\Kryptiq Corporation\GW\Bin>smtp_sink_register.bat

c:\Program Files\Kryptiq Corporation\GW\Bin>cscript smtpreg.vbs /add 1 OnArrival
 KryptiqSpoolFilter SpoolFilter.FilterObject "mail from=*"
Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.

Binding Display Name Specified: KryptiqSpoolFilter
Assigning priority (24575 in 32767)
Registered Binding:
 Event Name  :SMTP Transport OnSubmission
 Display Name:KryptiqSpoolFilter
 Binding GUID:{C12ECB83-BF0A-46B4-823D-8C4D212F5238}
 ProgID      :SpoolFilter.FilterObject
   Rule      :mail from=*
   Priority  :24575 (0 - 32767, default: 24575)
   ComCatID  :{FF3CAA23-00B9-11d2-9DFB-00C04FA322BA}

How can I debug this event sink and figure out why it is not processing any email that lands in the SMTP pickup directory, and instead the email passes through untouched? Are there IIS 7 requirements for SMTP Event Sinks that are different from IIS 6, such as new permissions?

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up vote 0 down vote accepted

According to the URL

IIS7 no longer uses the IIS SMTP event architecture, and instead you have to create an SMTP Receive Agent. (more information at

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I assume you resolved your issue but in case other people have a similar issue, make sure your assembly is signed and use regasm /codebase {your assembly name}


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