Article ID: 2590562 - View products that this article applies to.
Users in a Microsoft Forefront Online Protection for Exchange (FOPE) environment receive a non-delivery report (NDR) when they send email messages to a recipient whose messaging environment uses the Backscatterer.org service for mail security.
This issue occurs if all the following conditions are true:
Because the cause of the issue is rooted in the Backscatterer.org service, the resolution must be directed at Backscatterer. Microsoft Online Services does not support Backscatterer.org services. The following guidance is provided as-is and without any warranty to remedy unexpected mail rejections from recipient environments that use the Backscatterer.org service as a block list.
To resolve this issue, try one of the following:
Backscatter (also known as outscatter, misdirected bounces, blowback, or collateral spam) is the incorrect and automated bounce messages that are sent by mail servers, typically as a side effect of incoming spam. Because FOPE is a spam-filtering service, mail to nonexistent recipients and to other suspicious messages is rejected by our service. When that happens, FOPE generates a new NDR message and delivers it back to the "sender." Because spammers frequently use a forged or invalid "from" address in their messages, the sender address to which the NDR is sent may result in backscatter. When this happens, outgoing servers that are associated with the FOPE network may be listed on the Backscatterer DNS block list (DNSBL).
The Backscatterer DNSBL is a list of IP addresses that send backscatter. It is not a spammer list. According to the instructions on the Backscatterer website, the use of reject mode for all incoming mail is not a recommended configuration or use of that service. It should be used in safe mode to block messages where MAIL FROM is the following:
<>For more information about the correct configuration, visit the following Backscatterer.org website:
Microsoft is committed to enabling customers to have a secure email environment that is both spam-free and virus-free. As part of that commitment, FOPE takes many steps to make sure that mail that is filtered through our network does not contain unsolicited commercial messages.
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