A dual port ethernet card is a computer hardware device that provides two Ethernet ports for connecting to a network. It is used to connect two computers or other network devices together, allowing them to communicate with each other. It is also used to connect a computer to a router or switch, allowing the computer to access the internet or other network resources. Dual port ethernet cards are available in both wired and wireless versions, and are typically installed in the computer's motherboard. They are an essential component for any network setup.