CST8200 - Week 2: DNS Overview
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What is the primary function of the Domain Name System (DNS)?

  • To manage user authentication across domains.
  • To translate names to IP addresses and back. (correct)
  • To secure communications over the network.
  • To allocate dynamic IP addresses for devices.

In which scenario does a computer first check to resolve an IP address using DNS?

  • When it directly queries an external DNS resolver.
  • When it fails to connect to the DNS server.
  • When it accesses the HOST file for local mappings.
  • When it checks its localhost IP address. (correct)

What role does Dynamic DNS serve in a network?

  • It stabilizes static IP addresses for devices.
  • It allows identification of computers using dynamic IP addresses. (correct)
  • It allocates bandwidth based on device priority.
  • It provides a secure connection for certificate authorities.

What happens if a computer does not find the requested IP address in its cache or HOST file?

<p>It will request the information from its DNS resolver over UDP port 53. (D)</p> Signup and view all the answers

Which of the following services relies heavily on DNS for its functionality?

<p>User authentication processes. (C)</p> Signup and view all the answers

What is the primary characteristic of a secondary zone in DNS?

<p>It must conform to the name of an existing primary zone. (D)</p> Signup and view all the answers

What triggers a zone transfer between DNS servers?

<p>A secondary server requesting the transfer. (C)</p> Signup and view all the answers

Which option can be configured to determine how often a secondary DNS server attempts to renew its zone information?

<p>Refresh interval (D)</p> Signup and view all the answers

What happens if a traditional forwarder does not respond during a DNS query?

<p>The next forwarder in the list is queried. (C)</p> Signup and view all the answers

When configuring zone transfer settings, which option allows transfers only to specified servers?

<p>Allow zone transfers to specific servers (C)</p> Signup and view all the answers

Which of the following accurately describes the relationship between primary and secondary DNS zones?

<p>Secondary zones replicate data from primary zones. (A)</p> Signup and view all the answers

Which interval defines how long a secondary server should wait before retrying a failed zone transfer?

<p>Retry interval (D)</p> Signup and view all the answers

Which type of forwarder is configured in a separate Conditional Forwarders node?

<p>Conditional forwarders (D)</p> Signup and view all the answers

Which statement accurately describes a primary zone?

<p>Considered authoritative for the zone. (D)</p> Signup and view all the answers

What is the role of a caching-only server in the DNS architecture?

<p>Resolve queries and cache the results. (B)</p> Signup and view all the answers

In DNS, which type of record is specifically used to map IP addresses back to hostnames?

<p>PTR record (B)</p> Signup and view all the answers

What type of DNS query does a DNS server respond to with either the best information or a referral?

<p>Iterative query (A)</p> Signup and view all the answers

Which types of records are typically found in a forward lookup zone?

<p>CNAME, A, AAAA (B)</p> Signup and view all the answers

Which of the following accurately describes a secondary zone?

<p>It contains a read-only copy of resource records. (B)</p> Signup and view all the answers

What does accomplishing a recursive DNS query ensure?

<p>The server resolves the query itself. (A)</p> Signup and view all the answers

Dynamic updates in DNS records allow what functionality?

<p>Automatic modifications by DNS clients. (A)</p> Signup and view all the answers

What do MX records specifically indicate in DNS?

<p>The mail server for a domain. (C)</p> Signup and view all the answers

What is the primary function of Glue A records in a DNS context?

<p>To resolve NS record information. (B)</p> Signup and view all the answers

Which DNS resource record type is necessary for the proper operation of an Active Directory domain?

<p>SRV Record (C)</p> Signup and view all the answers

Which record type combines the function of both direct and aliasing linking of domain names?

<p>CNAME Record (B)</p> Signup and view all the answers

What aspect of DNS configuration does the SOA record specifically handle?

<p>Identifying the server primarily responsible for the zone. (B)</p> Signup and view all the answers

What is the primary purpose of a forwarder in DNS?

<p>To redirect requests to DNS servers that can resolve them. (D)</p> Signup and view all the answers

Flashcards

DNS Function

DNS translates computer names (like www.example.com) into IP addresses (like 192.168.1.1) so computers can communicate.

DNS Purpose

DNS allows people to use names instead of complicated IP addresses to access computers and various related services.

DNS Resolver

A computer program that queries a DNS server for IP addresses when a computer needs to find another computer's IP address.

DNS Resolution Process

The steps a computer follows to find an IP address from a hostname, first checking local resources and, if needed, querying a DNS server.

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Localhost

A special IP address range (127.0.0.1-127.255.255.254) that points to the computer itself.

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Secondary Zone

A read-only copy of a primary zone. It receives data from the primary zone and serves DNS requests for that zone.

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Primary Zone

The original and authoritative source of data for a DNS zone. It can be modified and its changes are replicated to secondary zones.

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Zone Transfer

A process of copying DNS data from a primary zone to a secondary zone to ensure consistency.

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Refresh Interval

The time a secondary server waits before requesting a new copy of the zone data from the primary.

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Retry Interval

The time a secondary server waits before trying to get zone data again if the initial transfer fails.

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Expires After

The time after which a secondary server considers its data outdated and must get a new copy from the primary.

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Conditional Forwarder

A DNS server configured to handle specific queries for certain domains by forwarding them to a designated server.

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Traditional Forwarder

A DNS server configured to forward queries for names outside its own zone to another server.

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DNS

A distributed, hierarchical database that maps domain names to IP addresses.

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Distributed Database

A database where no single server holds all the information.

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Hierarchical Database

A database organized in a tree-like structure, with parent-child relationships between its component data.

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DNS Zone

A grouping of DNS information (like a specific domain or subdomain).

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Resource Record

Data entry in a DNS zone, containing information about network resources.

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Iterative Query

A DNS query where each server responds with its best available information or a referral to another server.

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Recursive Query

A DNS query where the server follows a chain of queries, until it has the final answer, or states it doesn't know.

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Forward Lookup Zone (FLZ)

DNS zone containing records to translate domain names to IP addresses.

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Reverse Lookup Zone (RLZ)

DNS zone containing records to translate IP addresses to domain names.

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Authoritative Server

A DNS server that holds a complete, authoritative copy of a zone's resource records.

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Forwarder

A DNS server that receives requests it cannot resolve itself and redirects them elsewhere.

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CNAME Record

An alias for another domain name record.

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PTR Record

Resolves IP addresses to domain names (used in Reverse Zones).

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SOA Record

Start of Authority record, holds information about a zone's servers and data.

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NS Record

Specifies authoritative name servers for a zone.

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Study Notes

CST8200 - Windows Domain Administration

  • Course instructor: Denis Latremouille
  • This is a course on Windows Domain Administration.
  • Week 2: DNS (Domain Name System)

Agenda

  • Windows Server
  • Case Study Review
  • DNS Install, Configure, Manage
  • DNS Demo

Introduction to Domain Name System

  • Purpose: DNS resolves names to IP addresses (and vice versa)
  • Computers communicate using numbers, but humans prefer names
  • DNS is essential for many other services, including authentication and secure connections
  • Dynamic DNS enables locating computers even with changing IP addresses

DNS Order of Operations

  • When a computer needs an IP address:
    • Checks its own IP address (local host, 127.0.0.1-127.255.255.254)
    • Checks its cache
    • Checks its HOSTS file
    • Queries DNS resolver (UDP port 53) for the IP address

Introduction to Domain Name System (DNS) (continued)

  • DNS is a distributed, hierarchical database
  • Distributed: No single database holds all data
  • Hierarchical: No rigid structure for how information is stored and accessed.
  • Lookup involves multiple queries across a hierarchy of DNS servers

DNS Naming Hierarchy

  • Hierarchical structure
    • Root (e.g., (root))
    • Top-level Domains (TLDs) (e.g., com, edu, net).
    • Second-level Domains (e.g., microsoft, google, cengage).
    • Subdomains (e.g., msdn, technet).

The DNS Database

  • A zone groups DNS information for one or more domains and/or their sub-domains
  • Zones contain resource records, giving information on network resources
  • Resource records are identified by codes (e.g., A, AAAA, MX)

The DNS Lookup Process

  • Iterative Query: DNS server responds with best information or referral.
  • Recursive Query: DNS server processes query until resolution or "I don't know" message.
  • Typical DNS lookup involves both.

DNS Server Roles

  • Authoritative Server: Holds complete copy of a zone's resource records.
  • Forwarder: DNS server to which other DNS servers send unresolved requests for resolution.
  • Conditional Forwarder: Directs requests for specific domains to specific servers.
  • Caching-only Server: Fields queries, resolves recursively to root servers, then caches results

Configuring DNS

  • DNS Zones:
    • Forward Lookup Zones (FLZ): Translate names to IP addresses (A, AAAA, MX records).
    • Reverse Lookup Zones (RLZ): Translate IP addresses to names (PTR records).

Zone Types

  • Primary Zone: Read/write master copy of all records for a zone.

  • Secondary Zone: Read-only copy of all records for a zone

  • Stub Zone: Read-only copy of SOA and NS records. Necessitates A records to resolve NS ones.

Dynamic Updates

  • Options for dynamic updates:
    • Allow only secure dynamic updates (recommended for Active Directory).
    • Allow both nonsecure and secure dynamic updates.
    • Do not allow dynamic updates.
  • Enable DNS clients to register/update resource records dynamically with a DNS server when changes occur.

Creating DNS Resource Records

  • Resource records can be created dynamically or as static records
  • Dynamic records are created by DHCP server.
  • Static records are manually created by admins

Host (A and AAAA) Records

  • Use to map hostnames to IP addresses (A) or IPv6 (AAAA)
  • Used to configure basic host name resolutions.

Canonical Name (CNAME) Records

  • CNAME record acts an alias for another record.
  • useful for associating multiple names to single servers.

Pointer (PTR) Records

  • Used to resolve an IP address to a hostname.
  • Found only in reverse lookup zones.
  • Often created automatically with host records.

Mail Exchanger (MX) Records

  • Used by email services to find the mail server for a domain.
  • Used by outgoing mail servers to deliver email messages, using DNS lookup for the MX record

Service Location (SRV) Records

  • Specifies a hostname and port number for servers offering specific services.
  • Required for Active Directory operation, allowing computers to find specific services.

Creating Dynamic DNS Records

  • Dynamic DNS records get created/updated automatically by DHCP server.
  • Time-to-live (TTL) values are set for dynamic record expiration, preventing outdated records

Configuring DNS Zones

  • DNS Manager provides options for viewing and changing DNS zones.
  • Zone statuses, types, replication, dynamic updates, and aging options.

Start of Authority (SOA) Records

  • SOA record contains information about the server responsible for a DNS zone.
  • Includes details like the primary server, admin contact, serial number, and time-to-live information.

Name Server (NS) Records

  • NS records specify FQDNs and IP addresses of authoritative servers
  • Used for delegating authority to other name servers for subdomains

Creating Secondary Zones and Configuring Zone Transfers

  • Secondary zones are read-only copies of primary zones.
  • Zone transfers are necessary for keeping secondary zone data synchronized.

Zone Transfer Settings

  • Zone transfers can be initiated manually or through auto-refresh/DNS notify mechanisms.
  • Options for specifying servers to do zone transfers and timing.

Configuring Traditional Forwarders

  • Forwarders direct queries to other DNS servers.
  • Servers are queried in order of specification.
  • No response from forwarders triggers a normal recursive lookup starting at root servers.

Conditional Forwarders

  • Condition forwarders are advanced configuration to enable more advanced operations.

Monitoring and Troubleshooting DNS

  • Troubleshooting process involves determining that DNS is part of a name resolution process.
  • Includes monitoring of query and zone performances.

DNS Troubleshooting Tools

  • Windows provides various tools like DNS Manager, DCDiag, dnscmd, PowerShell, Event Viewer, dnslint, nslookup, ipconfig, Performance Monitor, and protocol analyzers for DNS operations

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Related Documents

CST8200 Windows Domain Administration (DNS) PDF

Description

This quiz covers key concepts in DNS (Domain Name System) as part of the CST8200 Windows Domain Administration course. Learn about the purpose of DNS, its order of operations, and its critical role in computer networking. Test your knowledge on how DNS resolves names to IP addresses and its importance in maintaining secure connections.

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