DHCP Server Configurations

Hambone_20003 · 09-12-2011, 04:50 PM

Hello All,

I currently have 2 DHCP Servers setup with the fail-over peer statements for redundancy. I would like to add a third server to this pair in another location just in case I loose connection to the network where the first two servers are racked.

My question is has anyone added a 3rd fail over peer to there DHCP? Is this even a possibility or am I going to have to rsync the files from the other server to the third server and turn it up manually in the event of a failure?

Any advice or possible configuration setups that anyone has would be greatly appreciated.

Thank You

Brian

dafydd2277 · 09-12-2011, 06:10 PM

Hi, HamBone,

According to the dhcpd.conf man page, it can't be done:

Quote:

The failover protocol allows two DHCP servers (and no more than two) to share a common address pool. Each server will have about half of the available IP addresses in the pool at any given time for allocation. If one server fails, the other server will continue to renew leases out of the pool, and will allocate new addresses out of the roughly half of available addresses that it had when communications with the other server were lost.

(I also note that failover only works for pools, so my assign-ip-addresses-from-a-central-config-file enterprise, using hostnames and "fixed-address," can't be set up for two redundant DHCP servers.)

Cheers!
dafydd

Hambone_20003 · 09-13-2011, 07:18 AM

Dafydd2277,

Thank you for posting back. I read what you have posted and that is currently what I have setup. I have two servers that split the pool and will handle DHCP if the other goes down. I was looking to split the pool possibly 3 ways but your post also covers that. I will just have to Rsync the leases and conf files over to the other server every 5 minutes or so and manually turn it up in the event of a failure.