Mystery call to 54.243.198.12:443

Question

Using an app to monitor my app outgoing calls (using the app "Network Connections"), I noticed that my app calls an AWS server (in North America) on IP 54.243.198.12:443 (and sometime AWS in Ireland at 23.21.121.219:443). I don't use and external package (Only Android's libraries). How can I found who send this call? I'm not sure how to narrow my question to not be "Too Broad". The question is simple, how to stop or catch all outgoing API calls from my app (but not my code).

Answer 1

I can't answer how to debug this from the Android side, although I'm sure there must be some way to intercept the API calls that open the network connection.

However, the SSL certificate offered by those hosts gives some interesting information:

$ curl -v https://54.243.198.12:443/
...
* Server certificate:
*  subject: OU=Domain Control Validated; OU=PositiveSSL Wildcard; CN=*.ipify.org
...                                                                    ^^^^^^^^^

It looks like ipify.org is a service to find out your host's public IP address. Maybe this provides a clue.