Domain Name System (DNS) is an industry-standard protocol used to locate computers on an IP-based network. Users can remember display names, such as www.microsoft.com easier than number-based addresses, such as 207.46.131.137.
IP networks, such as the Internet and Windows 2000 networks, rely on number-based addresses to transmit data throughout the network; therefore, it is necessary to translate display names (such as www.microsoft.com) into numeric addresses that the network can recognize (such as 207.46.131.137). DNS is the service of choice in Windows 2000 to locate such resources and translate them into IP addresses.
DNS is the primary locator service for Active Directory, and therefore, DNS can be considered a base service for both Windows 2000 and Active Directory. Windows 2000 provides functions that enable application programmers to use DNS functions such as programmatically making DNS queries, comparing records, and looking up names.
Many DNS functions are actually function types, in that there is a base name for the function, but its use depends on character encoding. For example, the DnsQuery function is listed in the function reference of the DNS Application Programming Interface (API) as DnsQuery, but its use in applications depends on whether the character encoding is ANSI (designated by appending _A to the function type name), Unicode (designated by appending _W to the function type name), or UTF-8 (designated by appending _UTF to the function type name). Therefore, the function call for the DnsQuery function would actually be one of the following:
DnsQuery_A (_A for ANSI encoding)
DnsQuery_W (_W for Unicode encoding)
DnsQuery_UTF8 (_UTF8 for UTF-8 encoding)
All functions that require this convention clearly state this requirement within the first few sentences of their function definition. Use the proper function name; for example, you cannot simply call DnsQuery instead of DnsQuery_A.
The Domain Name System is an open protocol. As such, collaborative efforts from the industry as a whole ensure that its implementation on various systems does not limit interoperability. The standards body overseeing such recommendations is the Internet Engineering Task Force (IETF). The following are IETF documents—some of them Requests for Comments (RFC), and some Internet Drafts—that are associated with DNS. For more information about any of these documents, visit www.ietf.org.
DNS-related RFCs
RFC 1034: Domain Names—Concepts and Facilities—Implementation and Specification—Application and Support
RFC 1035: Domain Names
RFC 1123: Requirements for Internet Hosts
RFC 1886: DNS Extensions to Support IP Version 6
RFC 1995: Incremental Zone Transfer in DNS
RFC 1996: A Mechanism for Prompt DNS Notification of Zone Changes
RFC 2136: Dynamic Updates in the Domain Name System (DNS UPDATE)
RFC 2181: Clarifications to the DNS Specification
RFC 2308: Negative Caching of DNS Queries (DNS NCACHE)
DNS-related Internet Drafts
Draft-ietf-dnsind-rfc2052bis-02.txt (A DNS RR for Specifying the Location of Services (DNS SRV))
Draft-skwan-utf8-dns-02.txt (Using the UTF-8 Character Set in the Domain Name System)
Draft-ietf-dhc-dhcp-dns-08.txt (Interaction between DHCP and DNS)
Draft-ietf-dnsind-tsig-11.txt (Secret Key Transaction Signatures for DNS (TSIG))
Draft-ietf-dnsind-tkey-00.txt (Secret Key Establishment for DNS (TKEY RR))
Draft-skwan-gss-tsig-04.txt (GSS Algorithm for TSIG (GSS-TSIG))