Non-Delivery Report (NDR)

Definition - What does Non-Delivery Report (NDR) mean?

A non-delivery report (NDR) is a report that is automatically generated by a mail server to inform the sender that their email message was not successfully delivered. The NDR comes in the form of an email from the sender's mail server and contains information on why the delivery was unsuccessful. Most of the time this is due to a wrong destination email address placed on the "To" field or the receiver's inbox being full and no longer able to receive new messages.

Non-delivery reports are also known as non-delivery receipts, bounced messages, non-delivery notifications (NDN) or delivery status notifications (DSN).

Techopedia explains Non-Delivery Report (NDR)

Non-delivery reports are generated by mail servers based on a standard SMTP 500 error coding system. Specifically, it is generated by the sender's mail server based on a SMTP 500 error code that is given by the receiver's mail server. But errors that bar the message from being delivered can occur at many stages during mail delivery, such as the sender's mail server being unable to find the receiver mail server for any reason, the mail having been received but the server storage suddenly becoming full so the mailer daemon cannot replicate the mail, or the receiver has configured the email server to forward emails to another mail server which has failed for some reason. All of these scenarios are valid delivery failure scenarios and have their own SMTP 500 code that informs the sender why the email has bounced.

Sample error codes for NDRs include:

  • 4.2.2 — The receiver has exceeded their mailbox limit
  • 5.1.x — Problem with the receiver email address
  • 5.4.0 — DNS problem
Share this:

Connect with us

Email Newsletter

Join thousands of others with our weekly newsletter

The 4th Era of IT Infrastructure: Superconverged Systems
The 4th Era of IT Infrastructure: Superconverged Systems:
Learn the benefits and limitations of the 3 generations of IT infrastructure – siloed, converged and hyperconverged – and discover how the 4th...
Approaches and Benefits of Network Virtualization
Approaches and Benefits of Network Virtualization:
Businesses today aspire to achieve a software-defined datacenter (SDDC) to enhance business agility and reduce operational complexity. However, the...
Free E-Book: Public Cloud Guide
Free E-Book: Public Cloud Guide:
This white paper is for leaders of Operations, Engineering, or Infrastructure teams who are creating or executing an IT roadmap.
Free Tool: Virtual Health Monitor
Free Tool: Virtual Health Monitor:
Virtual Health Monitor is a free virtualization monitoring and reporting tool for VMware, Hyper-V, RHEV, and XenServer environments.
Free 30 Day Trial – Turbonomic
Free 30 Day Trial – Turbonomic:
Turbonomic delivers an autonomic platform where virtual and cloud environments self-manage in real-time to assure application performance.