Creating a new server with the DNS Manager automatically creates the Cache.dns file needed to locate the Internet root name servers and a dummy boot file. Creating a new zone with the DNS Manager creates the file for that zone. All of these files are located in the %SystemRoot%\system32\Dns directory, and all except the dummy boot file are built from standard resource records.
A name server boot file points to sources of DNS information. Some of these sources are local files; others are remote servers. The way in which the boot file is configured controls whether the name server acts as a primary server, a secondary server, or a caching-only server. Its structure and the commands used in the boot file are covered in Appendix B.
The Microsoft DNS server can use the same boot file as a Unix BIND 4 name server. This allows you to copy existing configuration files from a Unix system and run them under Windows NT. However, if you use the DNS Manager to configure the name server, the system does not need or use a boot file. Instead the system boots from registry settings. The boot file contained in the %SystemRoot%\system32\Dns folder is just a dummy file that explains that the system is booting from the registry.
If you’re interested in finding out more about the boot file, see Appendix B and the sample boot file in %SystemRoot%\system32\Dns\Samples, or read the description of the named.boot file in DNS and BIND, by Liu and Albitz. This is the last we will mention this file. ...