Starting Firewall Quickly

Sometimes my isp's DHCP server takes a little while to "wake up" or something, so by the time my startup scripts get to the firewall, eth0 is not yet configured. Then when eth0 finally gets going, I have to open YaST and restart the firewall, because nothing works right. Is there a quick way of doing this without firing up YaST? Not that YaST is slow, but there must be a better way. Matt, always there with the newbie questions.