Can someone please explaind me what is DLR and how it used in sms gateways?

Question

Can someone please explaind me what is DLR and how it used in sms gateways?

Answer 1

It is a URL callback for Delivery Reports. Instead of the gateway logging the activity it will callback the provided URL using a querystring at the end with the parameters of the delivery report.

So in order for the URL callback to work you'll need a HTTP webserver with a URL that listens for incoming GET requests:

http://www.example.com/dlr.php

then requests are sent to it like so

"http://example.com/dlr.php?page=dlr&status=[status]&answer=[answer]&to=[to]&ts=[ts]&id=[id]"

The full listing of documentation can be found here.