TCPreen is a simple tool to monitor and analyze data transmitted between clients and servers through connection-oriented streams data such as a TCP sessions; it supports TCP over either IPv4 or IPv6. TCPreen is a command line tool used to monitor connection-oriented network transmission, such as TCP/IP streams. It acts as a bridge between the server and the client in a connection, displays any data that is sent either way, and optionnaly logs everything to a file. It can be useful for debugging, monitoring or reverse-engineering purposes.TCPreen focuses on the data stream (software/socket layer), not on the lower level transmission protocol as the packet sniffers do.TCPreen listens on a TCP port and wait for incoming connections to come in. Then, it forwards data sent by the connecting client to another server port (possibly on another computer) and forwards server responses back to the client.TCPreen can display data on your console in real-time and/or save it to log files for later reference. Various display formats are available.While it was originally meant to help developers reverse-engineer TCP-based protocols, it can also be very useful to debug network server or client software or for a system administrator to monitor a TCP service.