Microsoft windows 2000 DNS manual Fully-Qualified Query, Name Resolution

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computer, the same rule is applicable to every adapter separately. This feature is enabled by default. It can be disabled through the Registry.

Name Resolution

A basic name resolution request consists of a query for a given type of a DNS record with a given DNS name. The name to be resolved supplied in a query falls into one of three categories:

•Fully qualified. The name specified in the query is dot-terminated.

•Unqualified Single-Label. The name specified in the query contains no dots.

•Unqualified Multi-Label. The name specified in the query contains a dot(s), but is not dot-terminated.

Fully-Qualified Query

A fully-qualified name uniquely identifies a particular machine on the network and requires no alterations, for example ntserver.mydomain.microsoft.com.

If such a name needs to be resolved, first a caching resolver tries to resolve the fully-qualified query against its cache (note that the HOSTS file is preloaded in the resolver cache). If it fails then the fully-qualified query is sent directly to a DNS server. The caching resolver learns of lists of DNS servers it can query through the TCP/IP configuration of the local machine. A machine with multiple adapters may have multiple DNS server lists.

The adapters on a multi-homed machine may or may not be participating in a fully- connected network. If the networks are disjoint, the DNS namespaces on those adapters may also be disjoint. For this reason, queries must be sent to DNS servers on all adapters for complete name resolution. The response to a query can be grouped into one of four classes:

•A positive answer. The name exists and has data associated with it.

•A negative answer. The name does not exist, or the name exists, but with no associated data.

•A server failure. The server cannot service the request.

•No answer. The server does not answer within the timeout period.

The DNS servers in a list associated with a particular adapter are assumed to be members of the same namespace. Servers are queried in the order they are given in the list, which is defined by the servers priorities. If one server in the list returns a positive or negative answer, then no other servers in that list are posed the same question. The resolver may advance to the remaining servers in the list only if the current server does not respond or responds with a server failure (this scenario is slightly different for a multi-homed machine, as shown below). Should a server not respond, the resolver dynamically reorders the list changing the priority of the non- responding server (for more detailed information on this see the section on “DNS Server List Management”).

For efficiency, one fast adapter is considered the preferred adapter for name

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Contents Windows 2000 DNS Microsoft Corporation. All rights reserved Contents Designing a DNS Namespace for the Active Directory Summary Page DNS Fundamentals Standards and Additional Reading Name Services in WindowsDraft-skwan-gss-tsig-04.txt GSS Algorithm for Tsig GSS-TSIG History of DNSHierarchy of DNS Domain Names Structure of DNSDNS and Internet Int/net/orgCom Edu Gov Mil Army Microsoft Mit MydomainDistributing the Database Zone Files and Delegation TTLMicrosoft My domain ftp Ntserver Replicating the DNS databaseQuerying the Database NEW Features of the Windows 2000 DNSName Server Resolver Root-server Gov Whitehouse.gov Time to Live for Resource Records Updating the DNS DatabaseActive Directory Storage and Replication Integration Active Directory Service Storage ModelWindows 2000 White Paper Replication Model Controlling Access to ZonesZone Type Conversions Protocol Description Incremental Zone TransferSlave DNS Server Ixfr and DS Integration Dynamic UpdateZone Log File Master DNS ServerDynamic Update of DNS Records Update AlgorithmDhcp Client Mixed EnvironmentClient Reregistration Statically Configured ClientSecure Dynamic Update RAS ClientEstablishing a security context by passing security tokens Secure Dynamic Update Policy Controlling Update Access to Zones and Names DnsUpdateProxy GroupAging and Scavenging DNS Admins GroupAging and Scavenging Parameters DefaultEnableScavenging Scavenging Period DescriptionRecord Life Span Scavenging Algorithm Configuring Scavenging ParametersInteroperability Considerations Unicode Character SupportDomain Locator Finish IP/DNS Compatible Locator DNS Record Registration and Resolver RequirementsLdap.tcp.dc.msdcs.DnsDomainName Kerberos.tcp.dc.msdcs.DnsDomainName IP/DNS DC Locator Algorithm Finish Discovering Site specific DCsCaching Resolver Fully-Qualified Query Name ResolutionUnqualified Single-Label Query Using Global Suffix Search OrderUnqualified Multi-Label Query Using Primary and Per-adapter Domain NamesUnqualified Single-Label Query Scenarios Name Resolution ScenariosNegative Caching Fully-Qualified Query ScenariosMicrosoft Implementation of Negative Caching DNS Server List ManagementWMI Support for DNS Server Administration Administrative ToolsDNS Manager Using Wins and Winsr Records Interoperability IssuesUsing UTF-8 Characters Format Receiving Non-RFC Compliant Data DNS Server PerformanceUtilization Hardware components Sizing Server Capacity PlanningChoosing Names Internet Access ConsiderationsWindows 2000 White Paper Windows 2000 White Paper Windows 2000 White Paper VPN Com Yyy.com Zzz.com Windows 2000 White Paper Primary Zone YYY corporation ZZZ corporation VPN Firewall Computer Names Characters in NamesPer-Adapter Naming Full computer nameIntegrating ADS with Existing DNS Structure Domain name and sites. Active Directory domain name DNS Migration to Windows 2000 DNSPartitioning, and Replication Choosing your Zones Deploying DNS to Support Active DirectoryWins Referral Using Automatic ConfigurationIxfr Ixfr For More InformationWindows 2000 White Paper
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