Question : Change DNS replication from domain wide to forest wide

Working with the following domain and sub-domains:

- domain.local
- de.domain.local
- uk.domain.local
- se.domain.local

When the DNS zones and sub-domains were set up, some DNS zones had domain replication and some have forest replication. We want to change all zones in all domains to be forest replication.

For example, DNS servers that are part of domain.local have DNS zones for de.domain.local, se.domain.local and uk.domain.local. Let say under domain.local there is the zone for de.domain.local and it's set to domain replication with 100 records, but on a DNS server in de.domain.local, that same dns zone is set to forest replication and has 125 records. As far as I can understand, there is no replication between the primary domain and sub-domain for the same sub-domain zone, because they are both not set to forest replication. I'm having a hard time determining if I switch the domain replication setting (on domain.local for de.domain.local) to forest wide if it will over-write the existing forest wide zone in b.domain.local, or vice-versa?

I've attached a few screen shots as visual-aids to my question. One picture shows a DNS server in domain.local named "DC01", and one from de.domain.local named "APP01". In domain.local for DC01, it shows that the zone for de.domain.local is domain wide (not replicating with any other DNS servers outside of the domain). However, on APP01, it shows de.domain.local as being forest wide. This is true for other sub-domains and DNS servers. So to ask the question again, what will happen if I change a domain-wide to forest wide? Will the exisiting forest-wide update to the recently changed forest-wide, or vice versa? What is the best way to migrate all zones to be forest-wide replicated?

Thanks

Answer : Change DNS replication from domain wide to forest wide

The so called merger of the two zones won't happen. Nor the overwrite, the DNS zone that has just had the replication scope changed from domain to forest will not replicate to forest partition as there is a zone that already exists in there with that name. You can test this by creating two same name zone in both partitions and you may come across an error as "The DNS server encountered error 32 attempting to load zone test.test from Active Directory. The DNS server will attempt to load this zone again on the next timeout cycle. This can be caused by high Active Directory load and may be a transient condition."

What I would recommend is exporting the additional records and manually or via scripts add it to the forest wide replication zone and then delete the domain based one.