SMS Fake delivery receipts

The SMS messaging industry has been experiencing exponential growth of SMS fake delivery receipts in recent years. They are by far the most serious threat to the quality of SMS delivery and the most lucrative source of revenue for the companies which generate them. Fake delivery receipts are very hard to detect and, at times, almost impossible to eliminate completely.

There are two main sources and causes of fake SMS delivery receipts, namely MNO and SMS aggregator caused fake DLRS, which I will try to examine and propose certain solutions and tips.

Aggregator caused fake DLRS



1. Fake delivery receipts which affect all traffic. This is the most primitive approach and is rarely used nowadays.

1. Since fake DLRs affect all SMS traffic, it should be quite easy to detect by sending a test sms to a mobile test number, either your own or via 3rd party service provider, such as TelQ Telecom. You need to simply send a test message and verify real delivery.

2. Fake DLRs which affect all traffic besides whitelisted SMS test numbers.

2. In order to avoid your testing numbers getting whitelisted, we suggest not escalating fake DLR message examples to untrusted partners. Otherwise, sooner or later, they will end up being whitelisted. If possible, use several SMS test number providers (especially if you don’t have to commit). 

3. Certain aggregators may give fake delivery reports exclusively on bulk traffic. Hence, separate tests even on non-whitelisted test numbers would not help.

3. You may want to send a small trial campaign to a few dozen numbers, one of which would be your own mobile test number. 

4. At times you may encounter instances of SMS fake delivery receipts on a random % of your traffic. This is extremely difficult to detect, especially if the percentage is small. 

4. This is probably the most difficult problem to overcome and there is no easy solution for it. However, increasing the amount of test numbers and SMS tests themselves, as well as listening carefully to the feedback of your clients may increase your chances of eliminating such routes. 

MNO caused SMS fake delivery receipts



1. Filtering based on Sender ID type. Most often, operators may give fake DLRs on alpha sender IDs.

1. Test with various sender ID types (alpha, local numeric, international numeric, short code) on a live test number and determine which sender IDs get filtered. Rewrite the sender IDs into the sender ID type which delivers or route traffic based on specific sender type criteria. 

2. Filtering based on specific Sender IDs. Certain operators filter just some alpha or short-code sender IDs and allow others.

2. Testing with various sender IDs on a live testing number will certainly help, however, if there is a significant amount of filtered sender IDs, it is highly suggested to rewrite all senders into a range of numeric long-codes

3. Filtering based on throughput/bulk filters. Test message may deliver on a handset, however, when a batch of messages is sent, the operator will give fake DLRs.

3. This can be difficult to verify by direct tests. However, you may want to duplicate your test message and send it as a batch to a range of numbers, which will include your test number as well. Including incorrect numbers may also help, positive delivery on such numbers may give an indication that the operator is giving fake DLRs.

General tips

  • Try not to disclose your testing numbers to anyone, especially unreliable aggregators. Instead of a solution to your problem, you will have an even bigger issue when your test numbers get whitelisted. 
  • Issue your tests frequently, this will improve your chances of detecting an unreliable route.
  • Try to send test messages with general content of your live traffic, this will make it less obvious that it is a test number.
  • Never use “Test” or something similar as a sender ID of your message.
  • And, most importantly, stop using suppliers which frequently generate or sell you fake DLR routes.