Asterisk with 2 Network Cards

"PBX in a flash" Asterisk box needs a second Network Card so the IP Phones connect to it on the local LAN and uses the second Network card to connect to the Internet. This is necessary because there's a second local LAN that uses the same switches and another restricted corporate network gateway to access the internet. We will add the network card locally but we will need support to setup the Asterisk box to work as mentioned. Thank you.