Is it still possible to reject dhcp replies from certain servers? Here in the Netherlands ISPs provide you with a random pick of black box routers with their plans. Last year I had a VodafoneZiggo plan, offering 8 variants, and currently I have a KPN plan which has 12. Both times I received their most recent hardware model. The default connection method is to have your ISP router function as a gateway through which your connections pass via a (usually very poor) NAT engine.
Luckily I was able to put these devices in "bridge" mode through their respective front-end menus. The goal was to avoid as much software layers as possible, receive the external IP on my OpenBSD gateway box, as well as all unfiltered traffic. However, whenever the VodafoneZiggo router had a reboot cycle (e.g. when the ISP pushed a software update) it would first go into its default state - providing local dhcp et al. - before it would go into bridge mode shortly after. This consistently broke my setup. My current KPN router does things differently: the local dhcpd cannot be disabled even in this "bridge" mode. Meaning it will be the response that wins discovery every time. Again, breaking my setup. I solved these issues by putting the following in my dhclient.conf, resp.: reject 192.168.1.254; reject 192.168.100.1;
