COM port to Ethernet software is specially designed for sharing of serial ports. Its ability to share an unlimited quantity of COM port devices via network will make your computer a robust, cost-effective terminal server.
It not only shares RS232 over network, but allows to see (and to work with) serial device in virtual machine. So, I may say that this is the best feature for me.
It hasn't been easy, but I finally managed to find an app for COM-port tunneling that’s neither stone-age-old nor comes without any sort of tech support. And that’s Serial to Ethernet Connector, the one and only.