Messages from other transport agents can be deadlettered

This article applies to:

• MailMarshal Exchange 5.3 and above
• NOTE: Change of default behavior in version 7.1

Symptoms:

• Messages from other transport agents can be deadlettered

Causes:

• MailMarshal Exchange processes all mail flowing through the Hub Transport server by default, including messages that have been generated by other transport agents configured on the Hub Transport server, such as AV scanners' notifications or notifications generated by the Hub Transport Rules agent.

• In some rare cases, messages generated by other agents can be formed in unusual ways, and MailMarshal Exchange can deadletter these messages.

Resolution:

In MailMarshal Exchange release 5.3.2 and above, you can control whether MailMarshal Exchange processes messages created by other transport agents with a Registry setting. 

Note:

• In versions 5.3 and 7.0, all messages are processed by default.
• In version 7.1, messages from other transport agents are NOT processed by default.

Warning: Using the Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Trustwave cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Make sure that you backup your Registry prior to making any changes.

Version 7.X

1. On the Array Manager server, open the Registry Editor.
2. Navigate to the appropriate Registry location:
   • HKey_Local_Machine\Software\Wow6432Node\Marshal\MMExchange\Default\Engine
3. Under the Engine key, create a new value with the following properties:
   • Type: DWORD
   • Name: AllowOtherFileSources
   • Data: To enable mail to bypass the MailMarshal Exchange Engine, set this value to 1. To disable the bypass, set it to 0.
   • Default (if the value is not present):
     • In version 7.0 the default is 0 (disable bypass).
     • In version 7.1 the default is 1 (enable bypass). 
4. To apply the change, commit configuration.

Version 5.3

1. On the affected server, open the Registry Editor.
2. Navigate to the appropriate Registry location:
   • HKey_Local_Machine\Software\Wow6432Node\Marshal Software\MailMarshal For Exchange\Default\Engine
3. Under the Engine key, create a new value with the following properties:
   • Type: DWORD
   • Name: AllowOtherFileSources
   • Data: To enable mail to bypass the MailMarshal Exchange Engine, set this value to 1. To disable the bypass, set it to 0.
   • Default (if the value is not present):
     • In versions 5.3  the default is 0 (disable bypass).
4. Restart the MailMarshal Exchange Engine service.