How are you getting a 172.x.x.x address from the 3448 when you configured its LAN for 192.168.x.x? Are you saying the 3448 is getting a 172 address on eth0/1 (WAN)?
If so, that means PPPoE isn't working and you are just getting a DHCP IP address from the service provider equipment, which is setup in router/firewall mode.
actually the 172 is the providers internal ip and it assigns me a peer ip that is external. I know the authentication is working properly because if I put a bad user or pass I do not get any numbers. It is a fiber connection not dsl/cable if that makes a difference. i could also ping the external ip at one point doing route from wan ip to 172 internal isp ip then to external ip but still no browse. I have reset to default since then and use the 3448 behind another router and everything gets routed properly via dhcp on the wan. (which is actually LAN on the device im looking to replace with this.)
I am at a loss. It seems to be issue routing specifically with the ppoe configuration and something to do with this "peer ip" address?