dhcp/dns

i’m planning to install firewall using two NIC. changes on the router IP address or server address should be done. We have two server PDC and BDC NT server. The Exchange server is on the BDC as well as DCHP, WINS, DNS server. If I’m going to change the IP address of the PDC and BDC, do you think it will not affect our email to other site? we have five site.