Clearing the Domain Controller DNS Cache

Domain controllers can cache DNS responses in order to speed up future lookUPS. If the cache is full or if the domain controller is not up to date, it may result in incorrect or failed lookUPS.

One way to clear the domain controller DNS cache is to use the dcdiag tool. To use the dcdiag tool, you first need to enable Verbose logging on the domain controller. To do this, use the following command:

dcdiag /verbose

After you have enabled Verbose logging, use the following command to clear the domain controller DNS cache:

dcdiag /flushdns

Note: If the domain controller is using Active Directory replication, the replication partners may also need to be cleared. Clear the replication partner DNS caches using the following command:

dcdiag /flushdns replication

After the domain controller cache has been cleared, the dcdiag tool will return the following message:

DNS: Clearing global DNS cache on DC.

The domain controller can now start to load the DNS information from the global DNS server.