This example shows a DSL WAN connection with multiple IP addresses from the DSL ISP. It contains both Ethernet and HomePNA clients, but has no router.
1) The HomePNA clients are on the same subnet, i.e. 192.168.1.X, as the Ethernet clients. This is because the Ethernet to HomePNA bridge does not create another subnet.
2) The DSL modem to hub/switch connection may need to be made via crossover cable or normal UTP cable, depending on the modem’s LAN port configuration. See this page for more information on when to use a crossover cable.
3) All clients (even the HomePNA ones) are directly connected to the Internet. See this page for how to secure this network. You might consider running a personal firewall on each machine as additional protection.