How can I stop the Exchange SMTP service performing reverse lookups?

John Savill

January 12, 2000

1 Min Read
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A. Some SMTP hosts do a reverse Domain Name Service (DNS) lookup forsecurity reasons when an SMTP connection is established. If this reverse lookupfails to resolve properly, they will possibly drop the connection.

To disable reverse lookup for Exchange perform the following:

  1. Start the registry editor (Regedit.exe)

  2. Move to HKEY_LOCAL_MACHINESystem|CurrentControlSetServicesMSExchangeIMC Parameters

  3. Double click on DisableReverseResolve (or create of type DWORD if not there)

  4. Set the type to binary and enter 1. Click OK

  5. Close the registry editor

About the Author

John Savill

John Savill

https://savilltech.net

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