What Is Non-Delivery Report (NDR)?

When you email someone, it's like sending a message in a bottle. You send your message out into the world, and it floats around until it finds its destination. If that destination is full of messages, or if the recipient has moved on to another email account, your message may not reach its destination. That's where Non-Delivery Reports come in. A Non-Delivery Report (NDR) is an automatic report generated by the sender's mail server to inform them that their email message wasn't successfully delivered. When you receive an NDR, the delivery failure is explained in an email message from their mail server. This usually occurs because the destination email address is placed in the 'To' field or because their inbox is complete and they cannot receive new messages. Non-delivery reports, or non-delivery receipts (NDRs), indicate that a message has been sent to a recipient but that the recipient's email server has rejected it. They're also known as bounce messages, bounced messages, non-delivery notifications (NDNs) or delivery status notifications (DSNs). The SMTP 500 error is a non-delivery report generated by the sender's mail server based on a standard SMTP 500 error coding system. Specifically, it is caused by the sender's mail server based on an SMTP 500 error code given by the receiver's mail server. Errors that bar messages from being delivered can occur at many stages during mail delivery, such as when a sender's mail server cannot find the receiver's mail server for any reason or when the receiver has configured their email server to forward emails to another mail server which has failed for some reason. These are good delivery failure scenarios and have their own SMTP 500 code that informs senders why their emails bounced, and if you're an email marketer or sender, you should know them all!

By TechDogs Editorial Team

Trending Definitions

Internet of Things Gateway (IoT Gateway)

The Internet of Things Gateway serves as the connection point for all connected devices and the cloud in the realm of the IoT. Like a traffic cop, it directs data from all those smart gadgets to the cloud, which can be evaluated and utilized to make data-driven choices. So, what precisely is it that an Internet of Things gateway does? First things first, it's in charge of something called "data collection." That's correct; exactly like a detective gathering evidence at a crime scene, the IoT Gateway gathers all of the data provided by those many intelligent devices that are part of the Internet of Things (IoT). Following that, we have something called "data processing." The act of gaining insight from all of the data that has been gathered is referred to as "data processing." comparable to putting together all of the pieces of a puzzle to solve a crime. With an IoT gateway, you can leverage data processing to make data-driven choices from all that intelligent device data. Last but not least, we have something called "data communication." Transmitting information from the IoT Gateway to the cloud is known as "data transmission. It is the same as sending a message to the headquarters of the police department. You can use data communication to transfer data to the cloud when you have an Internet of Things gateway, where it may be processed and used to make data-driven decisions. Please tell us precisely if the Internet of Things Gateway serves what purpose. Because all of these intelligent gadgets produce so much data, it is essential to establish a connection between those devices and the cloud, where the data may be stored. This bridge is known as the "Internet of Things Gateway. You can make sense of all of the data created by all of those smart devices in the IoT by using data collection, data processing, and data transfer if you have an IoT gateway. This enables you to use the information to make decisions based on the data rather than on gut instinct.

Cellular Phone

A Cellular Phone, also called a cellphone or mobile phone, is a form of portable electronic communication that has become ubiquitous in contemporary society. Signals are sent and received via radio waves across a network of cells connected to and serviced by a central base station. A cellular phone's networked system enables it to make and receive conversations wirelessly over an extensive range, whether to a traditional landline or the internet. It allows individuals to maintain connections in the heart of a bustling metropolis or far from any human habitation. A mobile device, including the handset and the SIM (Subscriber Identity Module) card that stores the mobile phone number, is what the cellular network refers to when it talks about a phone. Switching between devices is made possible by the SIM card's ability to keep the user's essential information, including contacts and personal data. Since the introduction of the first mobile phone for sale in 1983, cellular technology has undergone significant development. Modern smartphones come in various sizes and forms and boast valuable features like high-resolution cameras, touchscreens, built-in GPS systems, and access to multiple apps and services. The broad adoption of cell phones is partly attributed to the devices' decreasing price and increased availability. An estimated 7.9 billion people in the globe will use mobile phones in 2021, making them one of the most ubiquitous and consequential innovations of our era. There are many positives to having a mobile phone. They make it possible for people to maintain relationships with others, no matter where they may be physically located. They enable remote work and communication, providing access to information, news, and amusement, and have thus become an essential tool for companies and organizations. The ability to quickly and easily contact emergency services after an accident or natural catastrophe has also made cell phones indispensable. They have also become an essential resource for activists, facilitating the coordination of demonstrations and social movements and recording human rights abuses. Despite their widespread usefulness, there are pros and cons to using a mobile phone. They have the potential to be addictive and a source of distraction, which can have adverse effects on one's work and relationships. Misinformation, hate speech, and invasions of privacy are all possible outcomes of the irresponsible use of such tools. Cell phones, which transmit data via radio waves over a wireless network, have become indispensable to our daily lives. It's been crucial in times of crisis and societal upheaval, keeping people in touch and providing them with news, entertainment, and information. Despite its flaws, it has become one of our most popular and significant technological advances.

Referential Transparency

Referential Transparency... that's a mouthful. Don't worry, dear friend, because we are here to break it down for you in an entertaining and informative manner. So, let's start with the fundamentals. Referential transparency is a property of functions in computer programming that allows them to be replaced with their output without changing the program's behavior. Okay, it sounds a little dry. Consider this: suppose you have a function that takes in some input and produces an output. If that function is referentially transparent, you can replace any instance in your code with its output, and everything will continue to work typically. Why is this significant, you may ask? For starters, it makes your code easier to reason about. You don't have to worry about unexpected side effects or interactions with other parts of your program if you know a function always produces the same output for a given input. Furthermore, referential transparency can aid in optimization. If you know a function is referentially transparent, you can cache its output and avoid running it for the same input multiple times. This can save time and resources, especially in data-intensive programs. Let us look at some specific ways referential transparency can manifest in code. Immutable data structures are one example. If a data structure is immutable, it cannot be changed after creation. This makes reasoning about the code more accessible and ensures that the same input produces the same output. Another case in point is the use of pure functions. A pure function has no side effects and always returns the same result for the same input. Pure functions are more predictable and accessible to test than functions with side effects because they do not modify any external state. So there you have it: a nutshell explanation of referential transparency. It may not be the most exciting topic on the planet, but it is critical for anyone who works with computer programs. You can write programs that are easier to reason about, more efficient, and more reliable if you understand how referential transparency works and how to use it in your code. What person wouldn't want that?