DC/DNS been offline for a few days, easiest way to get it back online?

[sidewinder]

On Monday we had a problem (think it was down to Hyper-V and its MAC address assignment) which meant our main DC/DNS/DHCP was acting up and no DNS was working properly. So as we have a backup DC (plus a 3rd on another site) I just installed DHCP on that one, and we've been running without the main one since.

 

Now want to bring it back online, mainly because it has most of the FSMO roles assigned to it. So am I likely to run into any problems just switching it on again?

 

AD - will there be any lasting problems with not having the DC with most FSMO roles online for a few days?

DNS - When I bring the main one back up, it's going to have out of date DNS records. Will it sync with the others or is it likely to poison the DNS database with old records?

Would it be easier to just delete the zone on the offline server and then setup DNS again on it?

[jamesreedersmith]

No just reboot it and stop the DCHP scope on one server or the other.

[Michael]

I agree, disable DHCP Server on the server you're bringing back online. Because everything is time stamped, information from the servers which have stayed live should replicate to the server you're bringing back online.