you need one 8 port switch, five straight ethernet cables with rj45 connectors on both end of the desired length. arrange them and connect one ond of each cable to the switch and other to the computers. after that assign static ip address 192.168.1.5, 192.168.1.6, 192.168.1.7, 192.168.1.8, 192.168.1.9 fo your computers with default subnet and blank gateway and dns. now try pinging each one of them and that's it.
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