We are running some tests in which the Android phone should fragment large IP packets before sending over wifi directly to a server. For some reason, the server is receiving the entire packet as can been seen on wire shark. We suspect Android is not fragmenting large IP packets. We set the MTU using an app. Is there any other way of setting the MTU? How to verify if Android is fragmenting large IP packets?
Setup a wireless sniffer in monitor mode. With monitor mode you can see all of the wireless traffic sent over a channel, including any management packets like beacons and control traffic like acknowledgments. At this level, you can see everything that is transmitted over the air on a channel and successfully received at your sniffer.