First: Since I use GPRS modem with integrated TCP/IP stack, does also header traffic is being billed?
Yes, it will be billed. BTW, one reason more to us UDP/IP
> Can somebody give me a little bit more detailed explanation about how security is being affected if mobile station has a static IP adress?
From my side of few, there is no reason based on security. With dymamic IP adresses you can handle more users in the same IP range, because they are never all online.
Regards
Meff
GSM / GPS / GPRS modem and module for vehicle tracking