A new, useful feature introduced in Exchange 2010 SP1 is the ability to apply “Error Policies” on a send connector. This should only be configured for send connectors that are used to send emails over well-defined communication channels that are expected to always be available, such as a send connector dedicated to send messages to MessageLabs, Postini, FOPE, Office 365 etc.
A 2010 SP1 send connector can be configured to downgrade authentication and name resolution errors, which would normally result in an NDR, to transient errors. In these cases, Exchange will attempt delivery again instead of issuing an NDR. This will help the Exchange admin in resolving the issue without filling user inboxes with NDRs.
Microsoft strongly recommends that this option should not be configured for your send connector which sends emails to all domains (*).
The “default” option for “ErrorPolicies” parameter behaves in the default way, an NDR will be generated for any errors encountered.
The “ErrorPolicies” parameter specifies how the communication errors encountered by the send connector are treated. The possible values are:
- Default – A non-delivery report (NDR) is generated for communication errors.
- DowngradeAuthFailures – All authentication and TLS errors are treated as transient.
- DowngradeDNSFailures – All DNS errors are treated as transient.
Multiple values can be specified for this parameter, separated by commas. This comes in handy if you want to ignore both authentication/TLS and DNS errors. Run the command below to ignore both errors
Set-SendConnector “To MessageLabs” –ErrorPolicies DowngradeAuthFailures, DowngradeDNSFailures
Single set of errors can be ignored as well with the command below.
Set-SendConnector “To MessageLabs” –ErrorPolicies DowngradeAuthFailures
Set-SendConnector “To MessageLabs” –ErrorPolicies DowngradeDNSFailures