Root Hint Facts
Root hints are pointers to top level DNS servers on the Internet.
- The Cache.dns file holds the 13 root hint addresses for the Internet root servers. The Cache.dns file can be found in two locations:
- %SystemRoot%\system32\dns\Cache.dns (the copy in use)
- %SystemRoot%\system32\dns\backup\Cache.dns (the copy reserved in the backup location)
- The Cache.dns file normally lists the NS (name server) and A (host name) records for the Internet root servers. You can change this file to list the records for your own internal root DNS servers if you are using DNS on a private network.
- You can configure root hints through the properties of a DNS server or by configuring the DNS server’s Cache.dns file. If the server is configured to load data from Active Directory, you must configure root hints using the DNS snap-in because the local Cache.dns is not used (the root hints data is stored in Active Directory).
- The root zone is at the top of the DNS hierarchy, and is named . (dot).
- If you have a root zone configured on a DNS server, the server will act as a root zone server. A DNS server configured as a root zone server will never use the root hints file (Cache.dns). It considers itself authoritative. Consequently, the server won’t access the Internet to forward DNS queries.
- If you want the DNS server to access the Internet, delete the root zone in the DNS console.