I just got a Zyxel Modem from Century Link and 5 usable Static IPs in a block of 8. I configured the modem for "transparent bridging" and configured the PPOE credentials on a DD-WRT router and now it ...

Regarding bridge mode e.g. one has a router-modem(as in 'home router' so it does NAT too and also a modem inside), and a router(i.e. a 'home/NAT router' with no modem), and one wants to connect them.