Edit APN settings for IPV4
First please forgive this post if it is not helpful, I didn't see a solution and came up with something that worked for me, so hope it will help others.
Problem: On my Moto XT1806 GS5+ I was getting no IPV4 connectivity only IPV6 (tested with app: Ping & Net by Ulf Dittmer from the play store).
The main issue this caused was that I couldn't view my security cameras via Sprint's network., It would only show cameras on my home WIFI.
To verify I used Ping & Net to try to ping google.com. The app gives you the option to use IPV4 or IPV6, as you can guess IPV6 succeeded and IPV4 gave no results at all.
With some guesswork I did the following to fix this:
Solution:
open dialer and typed *#*#DATA#*#* or *#*#3282#*#* selected apn settings then internet.
at the top right tap the 3 dots and select edit this prompted me to enter a passcode which after several guesses ended up being 6 zeros "000000". (maybe this is in the instructions somewhere? Don't know didn't look, kinda figured it would be posted already if it was).
then I was able to change the APN NI from x.ispsn to n.ispsn.
Waited a few seconds, turned on airplane mode and then turned it back off and then I was on 3G with IPV4. It would be even better if it was LTE with IPV4, I will continue to experiment, or maybe someone can step in and save me the trouble. maybe cinet.spcs?
Anyway it works for now as a workaround and I can look at my security cameras away from home again, hooray.