DHCP data does not fallback to primary server

Hi everyone,

I got this thing installed on Server 2008 R2. It works well however I was wondering about something....

When the backup dhcp server kicks in and starts handing out new leases and renewing other ones, all that new info is stored in the dhcp database of the backup server. What happens when I turn the primary dhcp server back on? All that data is lost. There is no process to dump the data from the backup dhcp server and have it imported back into the primary server when it comes back online.

Am I missing something? Was I supposed to run the dhcpredundancy service in the primary server as well and create a scheduled task on the backup server to dump the configs to the primary server also.

This works well, but what's the point of copying over the data from the primary server to the backup server if you're not going to copy the latest data back to the primary when it comes back online.

Any help here would be appreciated. Thank you.

Hi Theo

That is correct, the info from the backup DHCP is not imported to the primary DHCP when it comes up.
If this is a problem depends on how your system looks like. If you have many new computers coming and going every day this can be a problem.
But if you have about the same computers coming and going and you have longer lease time than the time you think is a possible outtage of the primary DHCP, it wont be a problem. And if you set the Conflict Detection Attemps to 2 as suggested in the installing instructions it is even better.
One thing to remember is to not make any reservations on the backup DHCP when it is up, they will be lost when the primary DHCP comes up again.

Well I went ahead and installed the software on my primary dhcp server as well, so now it looks to the backup to see if the dhcp service is running there. I also created the scheduled task to copy the dhcp configs from the backup to the primary. I'm trying to see if I can get that to run only when the dhcp service is running on the backup. So it appears to be working well having the dhcp redundancy service installed on both dhcp servers. Do you see any pitfalls with this setup?

Well, it could work. But to get the import to the main DHCP to run, you must manually stop the backup DHCP so the main DHCP starts automatically via the redundancy software. If you start the main DHCP manually, the import wont happen.