proxy server

Probably basic question but Im getting ready to setup Proxy server 2.0 on home network to practice for test. I have a external DSL 675 cisco router configured in ppp mode. I have a nt 4.0 box with 2 nics using bogus 10.0.0.x ip addresses. I have aquired 5 ip addresses from my isp. Now for the quesion do I need to assign real static ip addresses to both of the nics and router? Should I configure router in bridging mode?