Which content filter option should you turn on in the Exchange admin center?

Your company subscribes to the Office 365 Enterprise E1 plan. You are the Microsoft Exchange Online administrator.

In the last week, employees have reported that they are receiving non-delivery report messages from other companies. The employees have not sent messages to recipients within those companies.

You need to prevent non-delivery report messages from reaching employees.

Which content filter option should you turn on in the Exchange admin center?
A . NDR backscatter
B . Conditional Sender ID filtering: hard fail
C . SPF record: hard fail
D . Block all bulk email messages

View Answer

Answer: A

Explanation:

The non-delivery report messages the users are receiving are the result of Backscatter.

Backscatter is the automated bounce messages that are sent by mail servers, typically as a result of incoming spam. Because Exchange Online Protection (EOP) is a spam filtering service, email messages sent to nonexistent recipients and to other suspicious destinations are rejected by the service. When this happens, EOP generates a non-delivery report (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 a backscatter message.

References: http://blogs.technet.com/b/exchange/archive/2014/08/18/spam-email-and-office-365-environment-connection-and-content-filtering-in-eop.aspx