Swapping IP addresses between two domain controllers

Question

On our VMWare ESXi environment is a single domain controller (Windows Server 2008R2) installed. Now I have to upgrade it to a new server (Windows Server 2012R2) which should has the same IP.

Many applications (no reliable list of applications exists) point to the current DC (Windows Server 2008R2) as their sole LDAP source. Not sure if they point to the name or IP address. Also the other server in our ESXi has as the a static DNS IP address of our domain controller.

That is why I have to migrate it without breakdowns.

Have you got any experiences how can I realize that wihtout any issues after the change. Or are there some references from microsoft? Thank you in advance!

Solution

While knowing how to do this can be useful in certain situations, as EEAA pointed out, you should probably have two DCs instead of one. If for nothing more than a disaster recovery/ backup.

If you are not performing backups of your current DC... START PERFORMING AD BACKUPS BEFORE DOING ANYTHING ELSE.

You should be able to do this without too much headache. After making the change you should definitely make it a priority to document where references to your DCs are in your environment.

This should be done at a time to minimize downtime.

1. Bring up your new DC using a new static IP address. Have it DCPromo'ed in and make sure it's fully functional before proceeding. (Have the new DC point to the original for DNS)
2. Give the 2008R2 DC the new static address, and the 2012R2 DC the original IP.
   3. Client side DNS Settings on the DCs here are important, if you are keeping two DCs DNS should point to the opposite DC then itself. If you are only keeping the one, point DNS to itself on both.
3. Restart AD DS services on both DCs, as well as the netlogon service.
4. Check DNS to ensure that all the records have been updated appropriately (A, & SRV)
5. Check AD logs to ensure there are no issues with replication (either FRS or DFSR)

If you were going to remove the original DC, you would then:

1. Transfer any FSMO roles the DC holds
2. DCpromo the DC out
3. Verify it has been demoted properly and all SRV records have been removed from DNS.

If you still need a temporary fix for applications that point to a removed DC by name, you could add a CNAME record to DNS for that DC that points to the new DC.

Again, you should probably have two DCs.

Also, for further insight and information, see this other SF question: Windows 2003 DC to Windows 2008 R2 DC with same name and same IP that takes into account other factors that might be involved (same concepts apply in your situation still).

Comments

[EEAA]

Sounds like you probably need a second domain controller.

[kralyk]

Hope my edit is ok and helps.

[HostBits]

Works for me, every little bit helps :)

[HostBits]

@MaxMix I'm not sure I follow your question. Do you mean you'll be setting up two new DCs, both 2012R2, one of which will be taking the IP of the old DC?

[MaxMix]

@Cheekaleak Yes, that Im exactly meaning. I hope you have a answer for my question.