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How Fake DLR’s Devaluate a Well-Functioning SMS Market

Sending and receiving text messages seems pretty simple but is in fact every time a miracle that has many technical intermediate stations.

Recently, SMS is increasingly the subject of the phenomenon of Fake DLR (fake receipts), a counterfeit of the delivery receipt that some mobile networks return on request from each individual SMS.

3 Million Messages per Day

The servers alone process over 2,000 text messages per minute. 125,000 per hour, three million a day. That includes text messages for purposes such as mobile marketing, One Time Passwords (OTP), SMS reminders, etc. All those messages find their way from the sender to receiver, coming from B2B SMS applications like Campaigns or the sender's own SMS application and direct API connections to's SMS Gateway.

Read more: takes the next step in platform high availability >

SMS Routes and Delivery Receipts

Which route an SMS takes, depends upon a number of factors. The most logical route is from a mobile phone (P2P) or an application (A2P) to an aggregator (SMS Service) after which the message is delivered to the SMSC of a telecom operator. The operator forwards it to the operator the receiver is connected to. Almost every text message also produces two DLRs, a Delivery Receipt or Delivery Report. One delivery receipt tells whether the message is accepted or rejected, and the second indicates whether the message has been delivered or is failed. Such status updates are crucial because SMS is used in critical business processes. The DLR provides information on the delivery route and time, whether it ended up in a queue, or - at worst - the text has not arrived – it failed. The Retry System by, which sends a text message if delivery fails, depends on the DLR's text messages.

The Delivery Receipt (DLR)

The availability of DLRs depends on whether the network supports DLRs or not. In principle, operators and SMS services only work with networks offering this feature. If the SMS Gateway sends an SMS, there’s always a request to return a DLR. Service providers and their customers should be aware of the legal status of many business-critical messages. The process of delivery is seriously disturbed by the so-called Fake DLRs. Fake DLRs are - as the name states - fake delivery receipts. They pretend an SMS message has been delivered to the mobile phone. In reality, the operator or aggregator has done nothing with the message but throw it away.


SMS service providers have many difficulties figuring out who is responsible for sending back fake DLRs. The routes that text messages travel sometimes lead to different operators and/or SMS aggregators. Within this route, it may occur a fake DLR is returned. For the sender of the SMS, it is often not clear whether its partner is directly responsible for the fake DLR, because the partner often cooperates with a third party to deliver text messages. A Fake DLR shows that an SMS message has been delivered correctly, while the opposite is true. In a 'normal' failed delivery, the DLR clearly indicates that the text message could not be delivered for any reason. The only one who can actually discover this method of faking delivery is the customer who has sent the SMS messages.

Real-time logging, which shows exactly whether an SMS is delivered or not in combination with a test message to a mobile phone controlled by the client, could be the method to check whether an SMS arrives or not. If no text message on the mobile phone is displayed, but the DLR indicates it as delivered in the logging, you know you’re dealing with Fake DLRs. Another method to fight Fake DLRs is the use of so-called test boxes for voice and SMS. These boxes allow operators real-time testing of voice and text messages. cooperates with other companies and service providers to build a global test network. There are already 400 live destinations.


Another method to slightly influence the Fake DLR method is ‘punishing’ the ones responsible for Fake DLRs. works proactively to detect deliberate returned fake DLRs. This means that, after confirmation of actual fraud, the person responsible will be ruled out of handling SMS traffic coming from No SMS traffic means no work and therefore less income.

A Properly Functioning Market is Under Pressure

Unfortunately, the above methods are not completely infallible. That, and the fact that this fraud is difficult to detect, hence lead to an SMS market that is slowly losing its value. Already, margins on text messages are under pressure due to the rise of mobile internet, smartphones, and apps. In the short term, sending fake DLRs might be a lucrative business. However, in the long term, SMS users will put aside using SMS as a communication channel: After all, you don’t use something that doesn’t work.

The fake DLRs are a phenomenon that has recently gained ground and is considered a form of a cyber threat. and telecom partners have solved another issue called spoofing. is convinced that Fake DLR is a problem that can be dissolved quickly. 

Testing the Quality of Your SMS Routes Has Never Been This Easy

How can you ever really guarantee the quality of messaging routes when you’re dealing with fake DLRs, gray routes, and “whitelisted” test nodes?

Our SMS route testing tool Texter will resolve these issues for you. Texter works with a live community of more than 66.000+ users worldwide. Using the support from our community, we enable aggregators and operators to perform tests on real devices from people all over the world. Devices all over the world can be used to test messaging routes and guarantee the best quality of SMS messaging.

Texter, a Unique SMS Route Testing Tool that Uses Live Nodes
connects tens of thousands of companies with millions of consumers via their mobile phone each day. Behind the scenes, from our innovative platform, makes sure companies can use these millions of messages, phone calls and payments to become part of people’s lives.
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