There are multiple reasons for this but I will try not to get into too much detail on why this isn't possible. Here are a few though:
- Most (if not all) routers block unsolicited incoming traffic unless a port is opened up and forwarded to a device on your local network. This is for good reason. You would not want anyone in the world to access your local networked devices! This means that unless a device on your local network requested something from an outside address over the internet, any incoming packets that were not requested will be ignored. This helps to fight hacking and illegal or unauthorized access to local networks.
- The scan works by looking for a response from all possible network addresses on your local network. Generally and simply speaking there are about 255 possible IP addresses to scan on a typical home network. Over the internet (as opposed to your local network), your device wouldn't know which public (WAN) IP address to use in order to access your local network connection. Which leads us to........
- There are millions of internet IP address. It would take a very long time to scan all of those possible addresses, and for those who have setup their routers to forward a port to their DirecTV receiver, that receiver would appear in your scan (assuming you had the patience to scan all of those millions of IP addresses). Conceivably, you could wind up with thousands of receivers listed in the app. Which one is yours? Does anyone else have access to it? Yikes!
Hopefully this explains the reasons without going into too much detail. The short answer is that scanning for your receivers over an internet connection (as opposed to your local WiFi network connection) is impractical if not impossible from a technical point of view.
Note though that you can add and control one of your receivers over an internet connection, but it requires some preparation and manually entering your internet (WAN) IP address into the app. For more information, see this FAQ.Tags: Scanning