I will explain how i’m working now.
I have adsl modem connected on pc with winroute on firs lan adapter and second lan adapter is connected to switch where is quintum connected.
So pc have public ip and quintum have private ip – 192.168.0.2
Every time i have new public ip i have to change extip.
I can’t find more info how to connect quintum directly to modem so he will use PPPoe – so instead pc to dial adsl modem, quintum will connect to internet. I dont even have to know what public ip i have in that moment.