Packet Sender is described as 'can send and receive UDP, TCP, and SSL on the ports of your choosing. All servers and clients may run simultaneously' and is an app in the network & admin category. There are three alternatives to Packet Sender for Windows, Linux, Mac, BSD and Chrome OS. The best alternative is netcat, which is both free and Open Source. Other great apps like Packet Sender are SmartSniff and pwncat.
Netcat is a featured networking utility which reads and writes data across network connections, using the TCP/IP protocol. It is designed to be a reliable "back-end" tool that can be used directly or easily driven by other programs and scripts.