In order to play older games, like Red Alert, via LAN connections on newer operating systems you'll need to emulate IPX connections between the machines. There are a few ways to accomplish this.
For dos games you're in luck as DosBox comes with this support natively. Simply start the ipx server on one machine ipxnet startserver [UDP port] and then connect to it on the rest of the machines ipxnet connect <IP> [UDP port]
For windows based games you can use something like Kali which will give you a fairly robust interface, or something like ipxemu or ipxwrapper which will trick the games into thinking they are connected via IPX.