Microsoft

1. Microsoft®
Official Course
Module 7
Implementing DNS

2. Module Overview
• Name Resolution for Windows Clients and Servers
• Installing a DNS Server
• Managing DNS Zones

3. Lesson 1: Name Resolution for Windows Clients and Servers
• What Are the Computer Names Assigned to
Computers?
• What Is DNS?
• DNS Zones and Records
• How Internet DNS Names Are Resolved
• What Is Split DNS?
• What Is Link-local Multicast Name Resolution?
• How a Client Resolves a Name
• Troubleshooting Name Resolution
• Demonstration: Troubleshooting Name Resolution

4. What Are the Computer Names Assigned to Computers?
A hostname is a computer name that is added to a domain name
and top level to make a fully qualified domain name (FQDN)
Hostname
AcctDirPC
Domain
adatum
Top level
com
Fully qualified domain name = AcctDirPC.adatum.com
NetBIOS names are rarely used and are being deprecated in
Windows operating systems

5. What Is DNS?
DNS can be used to:
• Resolve host names to IP addresses
• Locate domain controllers and global catalog
servers
• Resolve IP addresses to host names
• Locate mail servers during email delivery

6. DNS Zones and Records
A DNS zone is a specific portion of DNS namespace
that contains DNS records
Zone types:
• Forward lookup zone
• Reverse lookup zone
Resource records in forward lookup zones
include:
• A, MX, SRV, NS, SOA, and CNAME
Resource records in reverse lookup zones include:
• PTR

7. How Internet DNS Names Are Resolved
.root DNS
Microsoft.com DNS
.com DNS
What is the IP address of
www.microsoft.com?
1
2
3
4
Workstation
Local DNS Server
5
The IP address is
207.46.230.219

8. What Is Split DNS?
• External ADI DNS servers host only records that are
resolved from the outside: mail and web server
• Internal DNS servers host domain computer records,
plus mail and web server in a perimeter subnet
Internal
domain
servers and
computers
Internal
Active Directory-
integrated-DNS
server
External
DNS Server,
mail server, and
web server
1 2 3

9. What Is Link-local Multicast Name Resolution?
LLMNR is an additional method for name
resolution that does not use DNS or WINS
• LLMNR is designed for IPv6
• Works only on Windows Vista, Windows Server
2008, and all newer Windows operating systems
• Network Discovery must be enabled
• Can be controlled via Group Policy

10. How a Client Resolves a Name
NetBIOS Name
Cache
WINS Server
Broadcast
DNS Resolver
Cache/Hosts file
content
Local Host
Name
LMHosts File
DNS Server
1
2
3
LLMNR
45
6
7
8

11. Troubleshooting Name Resolution
A new Windows PowerShell DNS module with numerous
cmdlets was introduced with Windows Server 2012
• More cmdlets were added with Windows Server 2012 R2
Command-line tools to troubleshoot configuration issues:
• Nslookup
• DNSCmd
• Dnslint
• Ipconfig
The troubleshooting process:
1. Identify client DNS server with nslookup or
Resolve-DnsName
2. Communicate via ping
3. Use nslookup to verify records

12. Demonstration: Troubleshooting Name Resolution
In this demonstration, you will see how to:
• Use Windows PowerShell cmdlets to
troubleshoot DNS
• Use command-line tools to troubleshoot DNS

13. Lesson 2: Installing a DNS Server
• What Are the Components of a DNS Solution?
• What Are Root Hints?
• What Are DNS Queries?
• What Is Forwarding?
• How DNS Server Caching Works
• How to Install the DNS Server Role
• Demonstration: Installing the DNS Server Role

14. What Are the Components of a DNS Solution?
DNS Servers on the InternetDNS ServersDNS Resolvers
Resource Record
Resource Record
Root “.”
.com
.edu

15. What Are Root Hints?
microsoft
DNS Servers
DNS
Server
com
Client
Root
Hints
Root (.) Servers
Root hints contain the IP addresses for
DNS root servers

16. What Are DNS Queries?
• Queries are recursive or iterative
• DNS clients and DNS servers initiate queries
• DNS servers are authoritative or non-authoritative for a
namespace
• An authoritative DNS server for the namespace either:
 Returns the requested IP address
 Returns an authoritative “No, that name does not exist”
• A non-authoritative DNS server for the namespace either:
 Checks its cache
 Uses forwarders
 Uses root hints

17. What Are DNS Queries?
DNS client
mail1.contoso.com
172.16.64.11
A recursive query is sent to a DNS server and
requires a complete answer
Local DNS server

18. What Are DNS Queries?
Client
Local
DNS server
Recursive query
mail1.contoso.com
172.16.64.11
Root hint (.)
.com
contoso.com
Iterative query
Ask .com
Iterative query
Authoritative response
Iterative query
Ask contoso.com

19. What Is Forwarding?
Client
Recursive query
mail1.contoso.com
Root hint (.)
.com
contoso.com
Iterative query
Ask .com
Iterative query
Authoritative response
Iterative query
Ask contoso.com
Local
DNS server
131.107.0.11
Forwarder
Recursive query
131.107.0.11
A forwarder is a DNS server designated to resolve
external or offsite DNS domain names

20. What Is Forwarding?
Conditional forwarding forwards requests using a
domain name condition
Client
Query for
www.contoso.com Local
DNS server
contoso.com
DNS
ISP DNS
contoso.com
All Other DNS Domains

21. Client1
Client2
ServerA
Where is
ServerA?
ServerA is at
131.107.0.44
Where is
ServerA?
ServerA is at
131.107.0.44
How DNS Server Caching Works
DNS server cache
Host name IP address TTL
ServerA.contoso.com 131.107.0.44 28 seconds

22. How to Install the DNS Server Role
DNS server installation methods:
• Server Manager
• Active Directory Domain Services Installation
Wizard
Tools available to manage DNS Server:
• DNS Manager snap-in
• Server Manager
• DNS Manager console (dnsmgmt.msc)
• DNSCmd command-line tool
• Windows Powershell
• Remote Server Administrative Tools

23. Demonstration: Installing the DNS Server Role
In this demonstration, you will see how to:
• Install a second DNS server
• Create a forward lookup zone by using
Windows PowerShell
• Configure forwarding

24. Lesson 3: Managing DNS Zones
• What Are DNS Zone Types?
• What Are Dynamic Updates?
• What Are Active Directory–Integrated Zones?
• Demonstration: Creating an Active Directory–
Integrated Zone

25. What Are DNS Zone Types?
Zones Description
Primary Read/write copy of a DNS database
Secondary Read-only copy of a DNS database
Stub
Copy of a zone that contains only
records used to locate name servers
Active Directory-
integrated
Zone data is stored in AD DS rather
than in zone files

26. What Are Dynamic Updates?
1. The client sends an SOA query
2. The DNS server returns an SOA
resource record
3. The client sends dynamic update
request(s) to identify the primary
DNS server
5. The DNS server responds that it
can perform an update
6. The client sends unsecured
update to the DNS server
7. If the zone permits only secure
updates, the update is refused
8. The client sends a secured
update to the DNS server
Resource
Records
DNS
Server
1 2 3 4 5 6 7
Client

27. What Are Active Directory–Integrated Zones?
Benefits of an Active Directory–integrated zone:
• Allows multimaster writes to zone
• Replicates DNS zone information by using AD DS
replication
• Leverages efficient replication topology
• Uses efficient incremental updates for Active Directory
replication processes
• Enables secure dynamic updates
• Delegates zones, domains, resource records for increased
security
Examples of contoso.com zones include:
• hqdc01
• filesvr01
• desktop101

28. Demonstration: Creating an Active Directory–
Integrated Zone
In this demonstration, you will see how to:
• Promote a server as a domain controller
• Create an Active Directory–integrated zone
• Create a record
• Verify replication to a second DNS server

29. Lab: Implementing DNS
• Exercise 1: Installing and Configuring DNS
• Exercise 2: Creating Host Records in DNS
• Exercise 3: Managing the DNS Server Cache
Logon Information
Virtual machines 20410C-LON-DC1
20410C-LON-SVR1
20410C-LON-CL1
User name AdatumAdministrator
Password Pa$$w0rd
Estimated Time: 40 minutes

30. Lab Scenario
Your manager has asked you to configure the
domain controller in the branch office as a DNS
server.
You have also been asked to create some new
host records to support a new app that is being
installed.
Finally, you need to configure forwarding on the
DNS server in the branch office to support
Internet name resolution.

31. Lab Review
• Can you install the DNS server role on a server
that is not a domain controller? If yes, are there
any limitations?
• What is the most common way to carry out
Internet name resolution on a local DNS?
• How can you browse the content of the DNS
resolver cache on a DNS server?

32. Module Review and Takeaways
• Review Questions
• Best Practices
• Common Issues and Troubleshooting Tips
• Tools