Hi,
I have two embedded devices trying to talk over a 4G gateway. One can successfully open a connection to the server, the other (using an old Microchip tcp/ip stack) can send a SYN, get a response, ACK it and send the HTTP request, but the HTTP request won't reach the server. Apart from window size and scaling (the one that won't work has a much smaller window size and no scaling), and a few options, the packets are almost identical.
It's also network dependant - everything is fine on EE, but breaks on O2.
Anyone have any suggestions?