netcat
Description
Netcat is a simple unix utility which reads and writes data across network connections, using TCP or UDP protocol.
Packages
source: netcat
binary: netcat
Usage Examples
The utility is actually named nc. Here's an example of how to open up a TCP listening socket on port 5060. If someone connects to and sends data to that port, it will be printed on the screen.
# nc -l -p 5060