socat is a command-line utility for transferring data between file descriptors, sockets, or other data sources and sinks. It can be used as a TCP port forwarder on a Linux or Unix system.
To use socat as a TCP port forwarder, you can use the following command:
socat TCP4-LISTEN:<local_port>,fork TCP4:<remote_host>:<remote_port>
This will listen on the specified <local_port> and forward all incoming connections to the <remote_host>:<remote_port> destination. The fork option allows socat to handle multiple connections concurrently.
For example, to forward all incoming connections on port 8080 to a remote host on port 80, you can use the following command:
socat TCP4-LISTEN:8080,fork TCP4:remote_host:80
You can also use the -d option to run socat in the background and the -v option to enable verbose output.
Keep in mind that you will need to have permission to bind to the specified <local_port> and to establish a connection to the <remote_host>:<remote_port> destination.
You can also use socat to forward other types of connections, such as UDP, Unix domain sockets, or serial ports. For more information about the options and usage of socat, you can refer to the socat manual page or the socat website.