Hi Minh-Quang Nguyen, We are able to connect and make GSM voice calls with mobiles. We are also able to attach and activate PDP context in case of GPRS. We are trying to configure the setup for GPRS connectivity towards internet. We understand that iptables needs to be configured for external connectivity. Can you let us know some more details of configuration to enable external connectivity from GGSN and "tun0" interface ?
Regards Prasad