What is dhcp redundancy checking for on the primary server?

What is the dhcp redundancy service checking for on the primary dhcp server to detect a failure before turning on the dhcp service on the backup server? Is it checking to see if the process is running or if the port is available or if the service is running or what?

Thank you.

The backup server sends a status query to the manin DHCP server service and if it gets a "status OK" answer it's all ok, but if it gets "status not OK" or no answer att all, it starts the redundant DHCP service.

Cool. Thanks for the info. I posed the same question to the Microsoft Cluster Forum. I'm trying to weigh the pro's and con's of deploying a clustered dhcp solution vs. using the dhcp redundancy solution. Here is a snippet of their answer:

Quote :

So for a DCHP resource, it just checks to see if the DHCP service is running.

If the resource fails these checks, by default the cluster will attempt to restart the resource. If this restart attempt is not successful, the group containing this resource will move to another available cluster node.

http://social.technet.microsoft.com/Forums/en-US/winserverClustering/thread/ee5c642b-4a84-4df5-95da-b85a103d2aef?prof=required

So pretty much we are monitoring the dhcp service in both cases. So far, I'm having a real hard time justifying the overhead and cost of a dhcp cluster in our enterprise.

Hello,

i would like to know which explizit tcp/upd port you are using for the checks (udp_67, udp_68)? The background is, that we use a new antivirus software and it shouldn't block that network port(s).

Thanks in advance

Regards,

kaeclioc