On Thu, Oct 22, 2009 at 03:57:40PM -0400, Ray Soucy wrote: > Really. How do we deal with rouge DHCP on the wireless LAN, obviously > this is such a complex issue that we couldn't possibly have a solution > that could be applied to RA.
Rogue DHCP doesn't immedately take down the entire subnet of machines with existing DHCP leases. It generally only affects new machines trying to get a lease, or RENEWing machines. The impact of a rogue RA is to immediately break connectivity for every machine on the subnet. Differing impacts leads to different risk assessments of which protocol to use. Regardless, modern wireless deployments use central controllers or smart APs that can filter DHCP. They could be extended to filter RA as well. And this whole point is rather moot because we have RAs and must deal with them. It is too late to get rid of the RA behavior of clients. Even if you don't want to use RAs, your hosts are going to still listen to them which means a Rogue RA is going to take down your network. We have this problem even on IPv4-only subnets, where a Rogue RA (usually a Windows box with routing turned on) breaks connectivity to dual-stack servers for machines on that subnet. Since the hosts prefer native IPv6 connectivity over IPv4, the hosts end up preferring the Rogue RA as the route towards the dual-stack server. We really just need to bug our vendors to implement Rogue RA protection for wired and wireless ASAP, wherever we are in our deployment of IPv6.
