is a critical aspect of the MS-203 Microsoft 365 Messaging exam, as these reports play a crucial role in troubleshooting issues related to email messaging. Non-Delivery Reports are system-generated email reports that inform the sender that their message couldn’t be delivered, typically due to an ongoing or occasional configuration problem.
Introduction to Non-Delivery Reports (NDRs)
An NDR is generated by email systems (like Microsoft Exchange Server or Office 365) whenever an email cannot be delivered to one or several recipients. These reports contain detailed information about the message, why it wasn’t delivered, and how the issue can potentially be resolved.
Types of Non-Delivery Reports (NDRs)
Microsoft NDRs can be categorized into two types based on the generating system:
- Original NDRs: Generated by a system that directly participated in trying to deliver the message. For example, if the recipient’s mailbox is full, the mailbox’s system generates the NDR.
- Probe NDRs: Generated by a system that runs tests to monitor the delivery path of the message. Probe NDRs don’t consist of an actual message and are used solely for determining system health and monitoring purposes.
Understanding NDR Codes
NDRs contain error codes that can be categorized into three parts based on their composition:
- General email delivery problem (2.X.X): Largely informational messages or warnings.
- Email delivery problem that demands manual intervention (4.X.X): Temporary issues which are often resolved automatically.
- Email delivery failed, no hope of successful delivery (5.X.X): Permanent issues requiring manual correction.
Analyzing Non-Delivery Reports (NDRs)
Analyzing NDRs typically requires some knowledge about system errors and understanding of common SMTP (Simple Mail Transfer Protocol) error codes. Here’s is how you can analyze NDRs:
Step 1: Check the error codes. For example, one common NDR error code in Exchange Server is “4.4.7”. The first “4” indicates a temporary error, the following “4” refers to a network error, and the final “7” suggests that the delivery time expired.
Step 2: Check the error messages. They usually give you a plain-english explanation of the problem. For example, you might see a message like “The server has tried to deliver this message, without success, and has stopped trying. Please try sending this message again.”
Step 3: Check the diagnostic information for administrators. These generally provide more detailed technical information about the error.
In conclusion, properly analyzing NDRs is crucial for maintaining smooth email flow in any system running Exchange Server or Microsoft 365. Knowing how to interpret the relevant error codes and messages, and correctly applying solutions, is integral to the tasks within the remit of the MS-203 Microsoft 365 Messaging exam. By acknowledging these reports and acting accordingly, you can help ensure an error-free messaging environment.
Practice Test
True or False: Non-delivery reports (NDRs) are messages that a mail system returns to the sender when it’s unable to deliver a message.
- True.
Answer: True.
Explanation: NDRs, also known as bounce messages, are automated messages from mail systems that indicate the failure of a message delivery.
An NDR occurs when:
- A. A mail server can’t find a recipient’s email address
- B. There are network issues preventing delivery
- C. An email is rejected due to the recipient’s mailbox being full
- D. All of the above
Answer: D. All of the above
Explanation: There can be many reasons behind an NDR, including an incorrect email address, network issues, or a recipient’s mailbox being over its storage limit.
True or False: In Microsoft 365, you cannot diagnose NDRs.
- False.
Answer: False.
Explanation: Microsoft 365 provides detailed error codes and messages in NDRs that can help you diagnose and fix non-delivery issues.
Which of these implies a mailbox delivery failure?
- A. 7
- B. 2
- C. 1
- D. 1
Answer: B. 2
Explanation: NDR code 2 implies that the delivery failed due to mailbox full.
In Microsoft Office 365, who receives the NDR for a failed delivery?
- A. The email sender
- B. The email recipient’s admin
- C. Both A and B
- D. None of the above
Answer: C. Both A and B
Explanation: Both the email sender and recipient’s admin are notified of the failed delivery present in an NDR.
True or False: In NDRs, the error code 550 X pertains to routing errors.
- True.
Answer: True.
Explanation: The code 550 X indicates that the destination mail server has identified a routing or address problem.
NDRs are commonly generated due to:
- A. Spam filters
- B. Incorrect email address
- C. Blocked attachments
- D. All of the above
Answer: D. All of the above
Explanation: The reasons for generating NDRs could be a spam filter rejecting the email, incorrect destination address, or blocked attachments.
True or False: NDRs cannot be customized in Microsoft
- False.
Answer: False.
Explanation: In Microsoft 365, you can customize NDR messages to provide targeted information to senders.
What does the NDR code 1 mean?
- A. Service unavailable
- B. Mailbox full
- C. Host not found
- D. Permission denied
Answer: C. Host not found
Explanation: In NDRs, code 1 implies a host not found problem.
True or False: You need administrative rights in Microsoft 365 to analyze NDRs.
- True.
Answer: True.
Explanation: In order to view and analyze NDRs in the Exchange admin center in Microsoft 365, you need to have administrative rights.
In Microsoft 365, where should you navigate to, in order to view NDRs?
- A. Mail flow > Message trace
- B. Mailbox > Trace
- C. Dashboard > Mailflow
- D. None of the above
Answer: A. Mail flow > Message trace
Explanation: The ‘Mail flow’ > ‘Message trace’ path enables viewing and analyzing NDRs in Microsoft 365’s Exchange Admin Center.
An improvement in NDRs in Office 365 is:
- A. Addition of a unique GUID value in trace data
- B. Support for multiple languages
- C. Simplification of error codes system
- D. All of the above
Answer: D. All of the above
Explanation: Office 365 has improved its NDR system by adding a GUID value to trace data for easier troubleshooting, supporting multiple languages, and simplifying the system of error codes.
True or False: The field “Remote Server returned” in an NDR provides information about the sending mail server.
- False.
Answer: False.
Explanation: The “Remote Server returned” field gives information about the receiving or destination mail server.
What does the NDR code 0 signify?
- A. Permission problem
- B. Syntax error
- C. Connectivity issues
- D. Unknown error
Answer: D. Unknown error
Explanation: NDR code 0 signifies that there is an unknown error that has occurred during the delivery of the email.
True or False: Analyzing NDRs can contribute to improving email security.
- True.
Answer: True.
Explanation: By identifying the reasons for email delivery failure through NDRs, organizations can rectify issues, update security measures, and improve the overall security of their email systems.
Interview Questions
What is a Non-Delivery Report (NDR)?
A Non-Delivery Report (NDR) is a report generated by an email server or an email client to inform the sender that a message was not delivered.
In Microsoft 365, where can you view and analyze NDRs?
NDRs can be viewed and analyzed in the Message Trace feature of the Security & Compliance Center or Exchange admin center.
What information does an NDR provide?
An NDR provides details about why an email failed to deliver, including the error code, message, and possible solutions.
What might be the cause if NDR 5.1.1 is displayed?
NDR 5.1.1 typically means the email address the sender is trying to reach does not exist.
How does an NDR 5.5.0 error occur?
NDR 5.5.0 often signifies a protocol error. It happens if there are problems in the SMTP protocol transaction.
What is a possible solution to an NDR 5.1.10 error?
NDR 5.1.10 signifies that the recipient’s email domain does not exist. A possible solution is to contact the recipient by another method to confirm the email address.
How can NDRs be avoided?
NDRs can usually be avoided by ensuring the recipient’s email address exists and is spelled correctly, and that the sending and receiving servers are properly configured.
How would you interpret NDR 5.7.1?
NDR 5.7.1 indicates that the recipient’s email server did not allow the sender or the sender’s server to send the email. It’s also known as “Permission to Relay” error.
What is the role of Diagnostic information for administrators in NDRs?
Diagnostic information provides more detailed information about the error, including the exact point in the SMTP conversation where the error occurred, which is helpful for technical troubleshooting.
What factors affect the generation of NDRs?
Some factors that affect NDRs include sender’s email address, recipient’s email address, email client’s settings, email server’s settings, and network connectivity issues.
What does NDR code 5.4.14 imply?
NDR 5.4.14 usually means that there’s a loop in the transport configuration causing the message to bounce back and forth between two servers or between two connectors in one server.
Where can you find enhanced status codes in NDRs?
Enhanced status codes can be found in the “Diagnostic information for administrators” section of the NDR.
What does the NDR 5.2.1 code imply in Microsoft 365?
The NDR 5.2.1 code usually implies that the recipient mailbox has some restrictions on incoming mail such as size or the number of messages.
How do you resolve the common NDR error, “User doesn’t exist in directory”?
To resolve this, verify the recipient address and resend the message. If the problem continues, check your directory server.
How would you interpret NDR 5.4.6 in Microsoft 365?
NDR 5.4.6 often implies a routing loop was detected, which means that an email message was stuck in a loop between servers. Resolving the misconfiguration in the transport settings can resolve this issue.
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