Microsoft windows 2000 DNS manual Fully-Qualified Query Scenarios, DNS Server List Management

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•negative response

•query t1 for boguz.dns.microsoft.com.

•negative response

•query e1 for boguz.dns.ntlab.microsoft.com.

•negative response

•query t1 for boguz.dns.ntlab.microsoft.com.

•negative response

•query e1 for boguz.microsoft.com.

•negative response

•query t1 for boguz.microsoft.com.

•negative response

•if a Registry key to send a single label query is set, then query e1 for boguz; if the response is negative, then query t1 for boguz

The Fully-Qualified Query Scenarios

Lookup a name on the Internet: ping www.microsoft.com.

•Query e1 for www.microsoft.com.

•Positive response

Lookup a name in the Windows NT Lab: ping www.ntlab.microsoft.com.

•Query e1 for www.ntlab.microsoft.com.

•Negative response

•Query t1 for www.ntlab.microsoft.com.

•Positive response

DNS Server List Management

If a DNS server does not respond to a query, its priority automatically decreases. This prevents the resolver from repeatedly timing out on servers that are not responding. However, as time goes on the priority of that DNS server could improve if it responds to further queries.

Negative Caching

Negative caching is the storage of the fact that the requested information does not exist. Just like the fact that a resource record exists and has a particular value can be cached, the fact of a non-existent resource record or name server can also be cached.

Negative caching is useful as it reduces the response time for negative answers. It also reduces the number of messages that have to be sent between resolvers and name servers, as well as network traffic generated by these messages. A large proportion of the DNS traffic on the Internet could be eliminated if all resolvers implemented negative caching.

Microsoft Implementation of Negative Caching

Microsoft’s implementation of negative caching is based on RFC 2308. It can be disabled by setting to zero the REG_DWORD NegativeCacheTime value under the

Windows 2000 White Paper

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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 Zone Type Conversions Controlling Access to ZonesReplication Model 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 ManagementDNS Manager Administrative ToolsWMI Support for DNS Server Administration Using UTF-8 Characters Format Interoperability IssuesUsing Wins and Winsr Records Utilization DNS Server PerformanceReceiving Non-RFC Compliant Data 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