The Microsoft operating system keeps a list of all unused public ports available. When a KEPServerEX Ethernet driver makes a connection to a device, it asks the operating system for a port and is given one (sometimes referred to as a TCP Socket). This port is used as a TCP or UDP source port until an error is received (like the device is not longer responding). At that time, the socket will be released and KEPServerEX will ask for a new one. The operating system automatically gives the next available port, thus ensuring that a bad message is not sent back erroneously from the device. Because the operating system is managing this, the ports are eventually re-used and there is no impact on the available system resources.