If everything else is working, Computer 3 will NOT have IP connectivity to the other two machines,
even if they are on the same switch. They must have IP addresses on the same network. (However,
if the IP addresses were all on the 192.168.12.x net and the gateway on the 192.168.112.x net, all
three machines could 'see' each other using IP. Computer 1, 2, and 3 just would not be able to get to
any other network.)