DNS & SITES-SERVICES OF Active Directory.pptx

ACTIVE DIRECTORY
SITES & SERVICES
DNS,

Configuring and Managing
the DNS Server Role

Skills Matrix
Technology Skill Objective Domain Objective #
Installing the DNS Server
Role
Configure a Domain
Name System (DNS)
server
2.1
Introducing DNS Zones Configure DNS zones 2.2
Configuring DNS Resource
Records
Configure DNS records 2.3
Configuring Active
DirectoryIntegrated Zones
Configure DNS replication 2.4
Introducing the DNS Name
Resolution Process
Configure name resolution
for client
2.5

Domain Name System (DNS)
 Because DNS plays such a key role in Windows
Server 2022.
 Without DNS, your network will most likely not
function — clients won’t be able to resolve names to
Internet Protocol (IP) addresses.
 In addition, Active Directory clients use DNS to
locate domain controllers.

HOST file
 Before DNS, name resolution was handled through
the use of text files called HOSTS files that were
stored locally on each computer.
 The HOSTS file listed each name of the host and its
corresponding IP address.
 Whenever a new host was added to the network,
an administrator would manually update the HOSTS
file with the new host name or IP address
information.

Domain Name System
 DNS benefits:
 Scalability
 Constancy
 Ease of Use
 Simplicity

DNS Namespaces
 A DNS namespace is a hierarchical, tree-structured
list of DNS host names, starting at an unnamed root
that is used for all DNS operations.
 Each domain can have additional child domains.

DNS Namespaces
 The DNS namespace has a hierarchical structure
and each DNS domain name is unique within a
namespace.
 At the top of the Internet DNS namespace is the
root domain.
 The root domain is represented by “.” (a period).

DNS Namespaces
 Under the DNS root domain, the top-level domains,
or first-level domains, are organizational types such
as .org, .com, and .edu.
 Generic — generic, top-level domain names.
 Country code — Examples of country code domain
names are .uk., .jp, and .us.
 Infrastructure domain — .arpa is the Internet’s
infrastructure domain name.

Traditional Top-Level Domain
Names
 com – Commercial.
 .edu – Education.
 .gov – Agencies of U.S. federal government.
 .net – Computers of network providers and ISPs.
 .org – Nongovernmental and nonprofit
organizations.

DNS Namespaces
 Second-level domains are registered to individuals
or organizations.
 Second-level DNS domains can have many
subdomains, and any domain can have hosts.
 A host is a specific computer or other network
device within a domain.

Fully Qualified Domain Name
(FQDN)
 DNS uses the fully qualified domain name (FQDN)
to map a host name to an IP address.
 An FQDN describes the exact relationship between
a host and its DNS domain.

DNS Server Types
 DNS server types are determined by the type of
zone or zones they host and by the functions they
perform.
 A DNS server may host either primary or secondary
zones or both.
 If the server doesn’t host any zones, it is referred to
a caching-only server.
 A server is said to be authoritative for a particular
zone if it hosts a primary or secondary zone for a
particular DNS domain.

Secondary Name Server
 A secondary name server hosts one or more
secondary zone databases.
 Because a zone transfer is used to create a
secondary zone, the primary name server and zone
already must exist to create a secondary name
server.

Caching-Only Server
 Caching-only servers do not host any zones and are
not authoritative for any domain.
 Caching-only DNS servers start with an empty cache
and then add resource record entries as the server
fulfills client requests.
 This information is then available from its cache when
answering subsequent client queries.
 A caching-only DNS server is valuable at a site when
DNS functionality is needed locally but when creating
a separate domain or zone is not desirable.

AD-Integrated Zones
 Zones are stored in Active Directory.
 No distinction between primary and secondary
servers.
 Changes made on one DNS server are replicated to
other DNS Server.

Installing the DNS Server Role
 Before you can use DNS Server Role, you must
install it with Server Manger.

Zones
 DNS hierarchical structure is that workload for
name resolution is distributed across many different
resources.
 For administrative purposes, DNS domains can be
organized into zones.
 A zone is a collection of host name–to–IP address
mappings for hosts in a contiguous portion of the
DNS namespace.

Zones
 Zone data is maintained on a DNS name server
and is stored in one of two ways:
 As a text-based zone file containing lists of mappings,
called a standard zone or a file-backed zone.
 Within an Active Directory database, called an Active
Directory–integrated zone.

Standard Primary Zone
 A standard primary zone hosts a read/write copy
of the DNS zone in which resource records are
created and managed.
 Only one server can host and load the master copy
of the zone.
 no additional primary servers for the zone are
permitted, and only the server hosting the primary
zone is allowed to accept dynamic updates and process
zone changes.

Standard Secondary Zone
 A copy of the zone file may be stored on one or more
servers to balance network load, provide fault
tolerance, or avoid forcing queries across a slow, wide
area network (WAN) link.
 This standard secondary zone is a read-only copy of
the standard primary DNS zone.
 Information from a primary zone is transmitted to a
secondary zone by performing a zone transfer, which
is done by copying the zone file from the primary
server to a secondary server.

Zone Transfers
 A zone transfer can be a full zone transfer (called
an AXFR), in which the entire contents of the zone is
copied from the primary server to the secondary
server during each zone transfer.
 An incremental zone transfer (called an IXFR), in
which only changed information is transmitted after
an initial AXFR, in order to cut down on bandwidth
usage between.

Forward Lookup Zone
 Most queries sent to a DNS server are forward
queries.
 They request an IP address based on a DNS name.
Includes Host (A) resource records that translate form
host name to IP address.

Reverse Lookup Zone
 The Reverse Lookup zone is in-addr.arpa domain.
 Enables a host to determine another host’s name
based on its IP address.
 Contains the Pointer (PTR) resource record that
translates from IP addresses to host names.

Stub Zone
 A stub zone is a copy of a zone that contains only
those resource records necessary to identify the
authoritative DNS servers for that zone.
 A stub zone is a pointer to the DNS server that is
authoritative for that zone, and it is used to maintain
or improve DNS resolution efficiency.
 The stub zone contains a subset of zone data
consisting of an SOA, an NS, and an A record.
 Like a standard secondary zone, resource records in
the stub zone cannot be modified; they must be
modified at the primary zone.

Resource Records
 The resource record is the fundamental data storage
unit in all DNS servers.
 Start of Authority (SOA)
 Name Server (NS)
 Host (A)
 Host (AAAA)
 Canonical Name (CNAME)
 Mail Exchanger (MX)
 Pointer (PTR)
 Service Record (SRV)

Start of Authority (SOA) Resource
Records
 Identifies which name server is the authoritative
source of information for data within this domain.
 The first record in the zone database file must be an
SOA record. In the Windows Server 2008 DNS server,
SOA records are created automatically with default
values when you create a new zone.

Start of Authority (SOA) Resource
Records

Name Server (NS) Resource
Records
 Identifies the name server that is the authority for
the particular zone or domain; that is, the server
that can provide an authoritative name-to-IP
address mapping for a zone or domain.

Name Server (NS) Resource
Records

A and AAAA Resource Records
 The A resource record is the fundamental data unit
of the DNS that is used to translate the host name to
the IPv4 address.
 The AAAA resource record is used to translate the
host name to the IPv6 address.
 The Pointer (PTR) resource record is the functional
opposite of the A record, providing an IP address-
to-name mapping, which is found in the reverse
lookup zones.

Canonical Name (CNAME) Resource
Record
 Sometimes called an Alias record, is used to specify
an alternative name for the system specified in the
Name field.

Canonical Name (CNAME) Resource
Record

Mail Exchanger (MX) Resource
Records
 Identifies the email servers for a domain.

Mail Exchanger (MX) Resource
Records

Service Record (SRV)
 Enables clients to locate servers that are providing
a particular service.
 Windows Server 2022 Active Directory clients rely on
the SRV record to locate the domain controllers they
need to validate logon requests.

Root Hints
 By default, DNS servers use a root hints file, called
cache.dns, on Microsoft DNS servers.
 The cache.dns file is stored in the %systemroot%
System32Dns folder on the server computer.
 When the server starts, cache.dns is preloaded into
server memory.
 By using root hints to find root servers, a DNS server
is able to complete recursive queries.

47
DNS Query Types
• Recursive DNS Query
In this query DNS server does not take the responsibility to best
answer to client. DNS server can’t forward this query to next
another DNS server.

48
• Iterative DNS Query
• It is a query in which the client accept the best available
answer from the DNS server. In case if the server dose not
know the answer.
• It may direct forward this query another DNS server. All Burdon
on local DNS server.
Continued……
.

50
• DNS Server Cache
• Is the temporary storage area in the DNS server that store the
most frequently or recently access records.
• This cache is clear when DNS service is stopped.
• DNS Zone
• Zone is a part of DNS database that contain record of domain or
multiple domain.
• Zone also contain a list of host name to IP address mapping for
that domain.
Continued…..

DNS Resolver Cache
 Any Windows computer, key the following at a
command prompt:
ipconfig /displaydns:
 To purge the cache, key the following at a command
prompt:
ipconfig /flushdns:

Forwarders
 A forwarder is a DNS server on a network used to
forward DNS queries for external DNS names to
DNS servers outside of that network.
 A conditional forwarder forwards queries on the
basis of domain name.

Dnscmd Command
 You can use the Dnscmd command-line tool to
perform most of the tasks that you can do from the
DNS console.
 This tool can be used to script batch files, to help
automate the management and updates of existing
DNS server configurations, or to perform setup and
configuration of DNS servers.

Advanced DNS Server Properties
 Advanced DNS server properties refer to the
settings that can be configured in the Advanced tab
of the DNS Server Properties dialog box.
 These properties relate to server-specific features,
such as disabling recursion, handling resolution of
multi-homed hosts, and achieving compatibility with
non-Microsoft DNS servers.

Advanced DNS Server Properties

Summary
 DNS names and the DNS protocol are required for
Active Directory domains and for compatibility with
the Internet.
 The DNS namespace is hierarchical and based on a
unique root that can have any number of subdo-
mains.
 An FQDN is the name of a DNS host in this
namespace indicating the host’s location relative to
the root of the DNS domain tree.
 An example of an FQDN is
host1.subdomain.microsoft.com.

Summary
 A DNS zone is a contiguous portion of a namespace
for which a server is authoritative.
 A server can be authoritative for one or more zones
and a zone can contain one or more contiguous
domains.
 A DNS server is authoritative for a zone if it hosts the
zone, either as a primary or secondary DNS server.
 Each DNS zone contains the resource records it needs
to answer queries for its portion of the DNS
namespace.

Summary
 There are several types of DNS servers: primary,
secondary, master name, and caching-only.

Summary
 A DNS server that hosts a primary DNS zone is said
to act as a primary DNS server.
 Primary DNS servers store original source data for
zones.
 With Windows Server 2022, you can implement
primary zones in one of two ways: as standard
primary zones (zone data is stored in a text file) or
as an Active Directory–integrated zone (zone data
is stored in the Active Directory database).

Summary
 A DNS server that hosts a secondary DNS server is
said to act as a secondary DNS server.
 Secondary DNS servers are authoritative backup
servers for the primary server.
 The servers from which secondary servers acquire
zone information are called masters.
 A caching-only server forwards requests to other DNS
servers and hosts no zones, but builds a cache of
frequently requested records.

Summary
 Recursion is one of the two process types for DNS
name resolution.
 A DNS client will request that a DNS server provide
a complete answer to a query that does not include
pointers to other DNS servers, effectively shifting
the workload of resolving the query from the client
to the DNS server.

Summary
 For the DNS server to perform recursion properly,
the server needs to know where to begin searching
for names in the DNS namespace.
 This information is provided by the root hints file,
cache.dns, which is stored on the server computer.

Summary
 A DNS server on a network is designated as a
forwarder by having the other DNS servers in the
network forward the queries they cannot resolve
locally to that DNS server.
 Conditional forwarding enables a DNS server to
forward queries to other DNS servers based on the
DNS domain names in the queries.

DNS & SITES-SERVICES OF Active Directory.pptx

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