hi, we plan to implement DHCP server farm in our network. Currently , there are there problems burning my head. could anybody do some help? 1. How to set up DHCP server farm with high availability? It's required to set up DHCP server with 99.999% available. To our experience, this needs to set up DHCP server on two sites and syncronize their content in real time. Beside this , we hope there should be as less modification as possible on edge router when one DHCP server is down. should anycast architecture helpful ? or should we just set up two dhcp servers on two sites and sync. with ISC DHCPD? is there any other method for fail-over and high availability? 2. How to set up accouting and authentication with DHCP? Regulation and content based pricing is demanded. So, we plan to authenticate customer and accouting on their usage. In previous list post, someone said Juniper could do radius before DHCP. Does this mean Juniper could authenticate user with radius (username/password) before DHCP ? Is there anyway to collect user traffic under DHCP ? 3. Someone said PPPOE is not good for customer looking for long time online , DHCP is an good option. But, to my understanding DHCP is just good for those looking for easy-transfer to IPv6 , because pppoe could also make user on line as long as possible. Is there any reference on DHCP server consideration on 4-to-6 migration? Joe