I am fairly new to the linux world but have a large networking background. I recently installed an OpenBSD box between my Cable modem and Linux Gateway(NAT/DHCP) Server with two bridged NICs to act as an invisible packet filter. Hopefully some of you have come across this before. Anyhow, the filter is working great except for one thing, when my ISP's DHCP server lease is over, it seems that the bridge is not allowing proper traffic either in or out so that my Linux box can retain or renew its public IP address. My only recourse is to plug the modem directly into the server, allow it to get its IP lease back, and then plug the BSD box back in and everything works fine. DHCP uses broadcast UDP over ports 67 and 68, which I have open, but yet I still have the problem. Here are the pf.conf rules for DHCP on the bridge. Any help would be much appreciated.

pass in on $PUBLIC inet proto udp from any to $MY_IP port = 67
pass in on $PUBLIC inet proto udp from any to $MY_IP port = 68