Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
netcat - Netcat is a featured networking utility which reads and writes data across network connections...
Kannel - Open Source WAP and SMS Gateway
Ettercap - Ettercap is a suite for man in the middle attacks on LAN.