You know what's badass? Last night I was up until almost 3am and I got ISC DHCPd configured for dynamic DNS updates and DHCP failover. I tested it by killing dhcpd on my primary dhcp server, and the secondary spewed to the log immediately saying it lost contact and proceeded to service the renewal request immediately after that. when the primary was restarted it updated the lease database from the secondary, and proceeded to serve the next request I threw at it. Boy am I impressed at that. :-) Working configs provided on request.