Android App Not connecting using WIMAX/4G

I have an Android application that uses URLConnection to connect to a REST service and gets some content. I am getting a ton of complaints that it doesn't work over a 4G connection like WiMAX, though it works fine over WiFi or 3G connections. Is there anything special I have to do before attempting the REST request to开发者_StackOverflow中文版 allow it to use the 4G connection? I am using Android 2.2.

PS: This is very hard to test as I only have Droid and a HTC Hero to work with.

These types of Android problems are difficult to debug as there are so many platforms and so many variables.

The only thing I can think of is that for some reason over 4G like Sprint your servers DNS is not registered so hitting your RESTful service like http://www.hello.com is not resolving to your actual server IP.

Because other than that it makes no sense why it would work on 3G/WIFI but not 4G.