I want to use Ubuntu as a firewall and wireless AP, with some external traffic passing through openVPN, and the rest just through a firewall

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http://askubuntu.com – I would like to do some configuration through Zentyal or a similar setup, but I am also willing to use config files. I am connecting to a commercial VPN using a username and password. I want that traffic to then pass through a firewall, then I want to provide services like dhcp and dns to a wired and wireless interface (wireless using hostapd). I also would like to have a similar network on two other interfaces that passes through the firewall but not the VPN. If possible I want both networks to see the local machines on each network and receive services such as a SAMBA and CUPS share, NTP, (HowTos)