I'm currently working on migrating our DHCP services from two Windows Server 2016 instances to a single Windows Server 2022 instance. The current setup has these 2016 servers load balancing DHCP at a 50/50 split, with both covering the same scopes. I need some guidance on the best way to transfer the DHCP configurations, including all lease information, during this migration.
Is it enough to simply export the DHCP configuration and lease data from the primary HA server and then import it into the new 2022 server? Or should I export and merge the scopes and leases from both servers?
I've also considered removing the secondary 2016 server from load balancing and then adding the new 2022 server to take its place. After that, I would drop the primary 2016 server once everything is confirmed working on the new instance. Once the scopes and leases are migrated, I'll disable services on the old servers, authorize the new one, and update the IP helpers.
I know this is straightforward, but I want to make sure I don't overlook anything crucial in the migration process.
4 Answers
Remove the failover relationship between your 2016 servers. Once that's done, keep DHCP on one of them (the primary one) and export that database with all the scopes and reservations. Afterward, stop the DHCP service on the 2016 server and un-authorize it. Then, import that database into your 2022 server and authorize it. It’ll help if you force renewals on a few clients to ensure everything's working correctly after migration.
If you can, I would suggest running the DHCP on a dedicated server. It's all about minimizing risk. The same goes for DNS if it’s part of your setup—having separate servers can greatly improve stability and management.
Microsoft actually has a guide that covers this migration process really well: [Microsoft Migration Guide](https://learn.microsoft.com/en-us/windows-server/networking/technologies/dhcp/migrate-dhcp-server). When migrating, you definitely want to export all scopes and leases to avoid potential IP conflicts. If you skip that, devices might hold onto their old IPs longer than you'd like, leading to issues.
Exactly! If you do have clients that we'll hold on too long, lowering the lease time will force them to renew and should make the transition smoother.
Just a heads up about consolidation. It can be risky! If something goes wrong with the single DHCP server, it could take down service for a lot of users. I’d recommend discussing potential impacts with your team before fully committing to combining the DHCP roles. In one incident I witnessed, we had major outages because of a centralized DHCP setup. It’s worth considering smaller, distributed setups as a fail-safe.
Yeah, and I’d recommend lowering the DHCP TTL during migration. This can speed up getting clients to recognize the new server, which could also help if you need to revert the changes later.