Dropbear SSH Server and Client - Dropbear is a relatively small SSH 2 server and client.
netcat - Netcat is a featured networking utility which reads and writes data across network connections...
OpenSSH - OpenSSH is a free version of the SSH connectivity tools that technical users rely on.
tcpdump - tcpdump is a common packet analyzer that runs under the command line.
Ethereal - Ethereal® is used by network professionals around the world for troubleshooting, analysis...
Packet Sender - Packet Sender can send and receive UDP, TCP, and SSL on the ports of your choosing.