Good day, Cloud Gurus,
and welcome back.
In this lesson we're going
to review the fundamentals of Windows Server DNS.
Let's take a look at what we're going to cover.
First up, we'll take a look at the fundamentals of DNS,
and then we'll dive into the domain name resolution process.
We'll cover off DNS zones,
and then we'll do a demo
where will install Windows Server DNS
and we'll configure some zones.
Now there's quite a bit to cover here,
and while DNS is a fundamental network service,
it's only a small fraction of the overall exam.
So if you've never managed DNS before,
this will potentially be quite a bit of information.
But if you have,
this lesson will be a great refresher
and enough for you to pass the exam.
And I'll include some links to some resources
if you need to brush up
on any of the concepts covered in this lesson.
All right, let's get started.
Domain Name System, or DNS,
is the process of converting a human readable name,
like barrierreefaudio.com, to an IP address.
And DNS is used to help us find resources.
But what you might not realize about a domain name,
is there's an implied dot the end of the name.
And that dot is referred to as the root zone.
And DNS is a hierarchy of zones.
Each domain is a zone,
and the root zone sits at the top of the DNS hierarchy.
Below the root zone sits the top-level domains,
things like.com and .net.
And a delegation of authority has occurred
between the root servers and the top-level domains.
And we'll cover authority in a little bit
more detail later in this lesson.
And below the top-level domains
sits the second-level domains.
And so it continues down the hierarchy.
And the process of converting a domain name
to an IP address is known as domain name resolution.
Let's take a look at that process now.
All right.
Let's quickly go over the DNS resolution process.
Because it's really important
that you have a good grasp of these fundamental concepts,
as they will help you greatly
when you're troubleshooting hybrid networking.
In this example, we have a Windows computer.
And in the DNS resolution process,
it's known as the DNS client.
And it wants to know the IP address
for www.barrierreefaudio.com.
When DNS client needs to translate a DNS name
to an IP address,
it first checks if the DNS name is its own name.
Next, the DNS client checks
if the name is in the DNS client cache,
and the DNS client cache contains all DNS names
previously looked up that haven't expired.
And we'll cover expiry in a little bit
more detail in following lesson.
It also contains everything in the host file.
And the host file is a text file
that maps DNS names to IP addresses.
And if the name is not found in the DNS client cache,
the client forwards the request
to its configured DNS server.
And that's where the DNS server has some decisions to make.
It's important to know that the DNS server
is responsible for returning the query to the client.
It doesn't hand off that responsibility to another server.
But it may go and talk to additional servers
on behalf of the DNS client.
When the DNS server receives the request,
it will first check if it is authoritative
for that DNS zone.
And authoritative means that the server
is responsible for the domain.
It owns it.
A DNS server that is authoritative for a zone
is called a name server.
If it is authoritative,
it will look in its own DNS database and respond.
It will not cache or forward a request
for a zone that it is authoritative for.
If it's not authoritative,
the DNS server will check the address in its own cache.
And if it is in its own cache,
it will respond with that entry.
And it's important to point out here
that the server cache is separate from the client cache.
A DNS server is also a DNS client.
And it will a DNS client cache and a DNS server cache.
The DNS server cache is checked
when a DNS client requests domain name resolution
not the DNS client cache on that server.
If the DNS server is still not able to respond,
it will use forwarders.
And there are 2 types of forwarders:
server forwarders and conditional forwarders.
A conditional forwarder is a forwarder
for a specific domain.
And this is checked first.
And a server forwarder is a catch all forwarder.
It is used if a conditional forwarder
is not configured or doesn't respond.
And finally, if all else fails,
the DNS server will use its configured root hints.
And root hints are addresses for the root name servers.
As you can see, there's quite a bit here.
And I'll demo this in the next lesson
to help cement some of these concepts.
Now let's move on and take a closer look at DNS zones.
A zone is a database for a DNS domain.
And there are 2 zone lookup types.
And that is the direction of lookup.
There are forward lookup zones,
which convert host names to IP addresses,
and there are reverse lookup zones
which convert IP addresses back to host names.
And then there are 3 zone types
and each of these can be configured
to be either forward or reverse lookups.
The first zone type to be aware of are primary zones,
and they store a writeable copy of the zone.
And then we have secondary zones.
And they store a read-only copy
that is replicated from a primary name server.
And finally we have stub zones.
And they store name server
and start of authority information
for a zone that is hosted elsewhere.
And start of authority information, or SOA information,
includes details like name servers.
And then we have zone storage.
Now zones can be stored as a standard zone
where the zone will be stored
on the name servers disk in a .dns file.
Or they can be Active Directory-Integrated
where they are stored in the Active Directory database.
And all Active Directory-Integrated zones
are read-write on DNS servers,
so secondary zones are not supported.
All right.
Now let's take a look at a demo
of configuring 2 DNS servers.
We have our existing network from the previous lesson
where we had 2 servers configured.
One on the internal network
and one on the external network.
In this demo we're going to use a new DNS server
on the internal network.
And I've reinstalled the external server,
converting it over from server core,
just to make it easier to follow along in this demo.
In this demo,
we will install the DNS role on each of the DNS servers.
And then we will create a DNS zone
on both the internal DNS server,
CORP-BNE-DNS01, and the external DNS server, DMZ-BNE-DNS01.
Let's jump into the demo.
All right.
Here we are logged onto our internal DNS server,
CORP-BNE-DNS01.
And we're going to go ahead and install DNS server role
on this server using server manager.
To do that we're going to select Manage,
then we'll select Add Roles and Features.
We'll click Next on the welcome screen.
We're doing a role-based installation, so we'll select Next.
We'll go ahead and use the current server
so we'll select Next.
And we're adding the DNS server role.
So we'll select that and we're going to add
the required remote server administration tools for DNS.
So we'll go ahead and select Add Features,
and then we'll go ahead and select Next.
We're not adding any additional features
so we'll go ahead and select Next.
It gives us a bit of an introduction to DNS.
We'll go ahead and select Next.
And then confirmation before we install.
So we'll go ahead and select Install.
All right, this will just take a moment to complete.
So we'll come back when this is done.
All right, with the DNS role successfully added,
we're going to go ahead and close the wizard.
And then we'll close server manager.
And then we'll go ahead
and launch the DNS server management tool
from administrative tools.
So we'll select Start,
and then Windows Administrative Tools,
and we'll open up the DNS Management console.
All right.
Now we're going to go ahead
and configure a forward lookup zone
for corp.barrierreefaudio.com.
So we'll select our server and we'll expand this node.
We'll select Forward Lookup Zones.
We'll right click and select New Zone.
We'll select Next on the welcome screen.
And we can see the types of zones
that we covered in this lesson.
We're creating a primary zone, so we'll select Next.
We need to provide a name for the zone.
This zone is corp.barrierreefaudio.com.
So we'll go ahead and provide that name.
And we'll go ahead and select Next.
It's going to install the zone information in a file.
That's fine. We'll go ahead and select Next.
We're not going to configure dynamic updates
so we'll go ahead and select Next.
And then we'll go ahead and select Finish.
Our forward lookup zone has been configured
on our internal DNS server.
All right, now let's jump and install
and configure a DNS server on our external DNS server.
Here we are on our external DNS server.
We're going to go ahead
and install the DNS server roll on this server.
But we're going to use PowerShell to install this time.
So we'll right click the Start button
and we'll select Windows PowerShell Admin.
And we're going to install the DNS server role
using the Install-WindowsFeature PowerShell command cmdlet.
And we're going to include the management tools.
And we'll go ahead and press Enter to run that.
This will just take a moment to complete
so we'll come back when this is done.
All right.
With the DNS role now successfully installed
on our external DNS server,
we're going to use the DNS Management console
to configure a zone for barrierreefaudio.com.
We'll go ahead and launch administrative tools.
And then we'll launch the DNS Management console,
navigate to our server,
expand that node,
and we'll right-click Forward Lookup Zones
and select New Zone.
All right.
And you're already familiar with this process
having just configured the internal DNS zone.
So I'll go ahead and configure the external zone,
and I'll come back when this is done.
All right.
Now that we have our internal
and external DNS servers configured,
we're going to use these servers in the following lesson
to explore domain name resolution.
That's it for now.
Let's wrap up this lesson
with a bit of a summary of what we've covered.
All right.
So what have we covered in this lesson?
A DNS zone host the resource records for a domain.
And DNS zones can be either forward or reversed lookups.
A primary DNS server is a read-write copy of a zone
whereas a secondary zone
are read-only copies of the zone transferred
from a primary zone.
And on domain controllers,
zone information can be stored
in the Active Directory database.
And these are referred to
as Active Directory Integrated Zones.
All right.
That concludes this lesson.
Thanks for being with me
and I hope you found it useful.
And I look forward to seeing you in the next lesson.