Hey @Sebastian-Gonzalez ,
Yep, that explains why you were having name resolution issues if one DC wasn't available. Once you transition to AD integrated zones, those issues should be gone!
Luckily, it's a pretty painless transition. You should be able to go to the properties of the zone and on the general tab, click change next to "Type". There you will see a checkbox for "Store the zone in Active Directory" (Primary should already be selected).
You will need to remove the zone from the other domain controller. Once you change the zone on the first DC to AD integrated, the DCs will replicate, including the new zone. You don't want an existing zone with the same name on the second DC. You also need to maintain name resolution for the clients throughout the process. Here's my suggestion, I;m sure there are many ways to accomplish this.
- Use DHCP to assign the appropriate preferred and alternate DNS server addresses.
- Remove the zone from one domain controller
- Change the zone on the other domain controller to AD Integrated
- Use AD Sites and Services console to force replication (probably not necessary, should replicate the change pretty quick)
- Verify the second DC now has a copy of the new AD Integrated zone
Keep in mind that once yo remove the zone from the one domain controller, clients using that server for DNS will not have name resolution until the AD integrated zone replicates. The whole process shouldn't take long, assuming everything goes as planned. But......you might want to do this at the end of the day just in case.