Allow DHCP Server traffic on ICF enabled Windows Server 2003
If you want to run DHCP server on a ICF enabled server computer:
Add UDP ports 67 and 2535 to the Windows Firewall exceptions list on the DHCP server.
If you want to find more information on ports which need to be opened on ICF in order to let it run properly, please reference here:
http://technet2.microsoft.com/WindowsServer/en/Library/09008ddd-0f9b-4c1c-9a15-d41c709d95691033.mspx?mfr=true