Most mobile internet providers don't give unique IP addresses to mobile hosts (due to lack of sufficient IPv4 addresses) and don't route ingoing connections. Extra price plans with public accessible IP might be available.
IPv6 will hopefully change things, but it's not yet supported by most mobile terminals as far as I'm aware of.
In my application SIM900 makes connection with server and listen to it and server has to put data on TCP.how can i do it?in HTTP we make request and gate data bt in this no request is made.i need to use SIM900 as TCP server only?