In a message written on Mon, Aug 13, 2012 at 08:51:09AM +0000, Joe wrote:
We are considering setup reduant DHCP server clusers by using anycast.
I already see people pointing out problems with Anycast here, but no one pointing out the best available solution. Assuming your DHCP servers are properly clustered, simply have your routers relay all requests to both servers. Here's instructions on setting up ISC DHCPD for redundant (pooled) servers: http://www.madboa.com/geek/dhcp-failover/ Then configure your routers to send to both DHCP servers with multiple helper-address lines: interface Gig0/0 ip helper-address 10.0.0.1 ip helper-address 10.128.0.1 The way this work is when a box comes up the router sends DHCP requests to both servers. The DHCP server that reponds first will be used by the client, which will complete negotiation with that server via unicast. The two DHCP servers will then synchronize their pools. Works great, no single point of failure, no anycast. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/