Hello and welcome to the DNS server of your session and this session I'll try to present briefly the
information regarding DNS technology in the perspective of Windows Server System.
Real talk about DNS naming system itself.
Have a look at DNS architecture and its components will compare DNS server corruption and client side
resolver Cashen DNS referrals and Guerrero's look at types of resolution requests and DNS forwarders
or various name resolution.
We'll go through Ozon types DNS records find what is a re-integrated zone and also reveal mansion's
some utilities to deal with DNS related issues Domain Name System place one on the most central role
in Windows server infrastructure domain services.
So what is DNS basically DNS is a structured database which is usually kept on domain controllers.
It is responsible for storing and resolving all the name on your network.
For instance if I open Crome and browse to Google dot com my internet providers DNS server is resolved
in Google dot com to an IP address on the Internet.
So each side has its IP address and the people cannot remember all their addresses IP addresses which
are on the Internet.
So that's where DNS comes into play.
It resolves IP address to Google dot com two sites name and my page open successfully.
Here are some components to understand DNS architecture better.
First of all DNS namespace DNS standards define a restructured namespace in which each branch of the
tree identifies a domain is your domain contains a collection of resource records that contain host
names IP addresses and other relevant information.
Corporations are attempts to retrieve specific resource records from a particular domain further.
They have name servers a DNS server is a service running on a server computer that maintains information
about the domain tree structure and contains authoritative information about one or more specific domains
in the structure.
This application which is run on our server is capable of responding to Glarus for information about
the domains for each U-2s this Soroti and also of Forward in queries to other domains which are not
in its authority.
This enables any DNS server to access information about any domain in the tree.
So think about name server as about a computer which stores information about namespace and is authoritative
for this information.
And what about resolvers resolver is a client program for example or my personal computer or some other
client that generates DNS queries and sends to a DNS server for fullfilment a resolver has a direct
access to at least one default DNS server and can also process referrals to direct its queries to other
servers when necessary.
So think about Arizona or as about a program which is set up on your computer and make squarest to name
servers which are responsible for namespace.
In order for the DNS server to do recursion properly it first needs some helpful contact information
about other DNS servers in Legionnaire's the main namespace.
This information is provided in the form of rude hints at least of preliminary resource records that
can be used by the DNS service to likit are the DNS servers that are authoritative for the root of the
DNS domain name space tree.
Here we can see an example of Reclast from DNS client to DNS server.
And then the request goes to route DNS server down to the top level domain.
This is called called top level domain.
After that it goes to second level domain
and subdomain.
Please note that we have a rude heathen's file which is kept on preferred DNS server every DNS server
on mostly every DNS server has routine's file.
Take a look at another example of the Collines DNS server forwarding the request to the second level
domains or a resolver of client requests and information from DNS server DNS server for verts to root
name server gets the reply then forwards that to top level domain authoritative server gets the reply.
And finally it gets the reply from second level domain authoritative server which is needed and replies
to the client on the slide.
We can see an example of recursive Clarie flow.
Please take a look how recursive glary happens.
So here is Querrey to our DNS server and DNS server makes all the work it Queiroz all the servers from
routines until it gets an answer for the requested DNS server which is also read caitiff for the requested
euro and only then it answers to the client.
This the needed information
on the second slide.
We have an example of iterative Querrey when resolver gets all the information by itself so it asks
DNS server DNS server answers that it doesn't know such address and it asks root server or servers that
doesn't know such address please ask first level domain result or asks first level domain to your town
so that it doesn't know such a name.
Please ask the second level domain and to the second level domain.
Answer yes or no such name please.
Got this information.
On the FirstLight recursive Querrey DNS server makes all the work for the resolver.
And on the second slide DNS server only answers does it no or it doesn't know the information about
the requested your real Dennis Suro question is an important element of the DNS architecture because
it reduces the number of requests sent to the domain servers.
The amount of time the DNS data remains cached on a server is called.
It's time to leave or TTL an abbreviation for it.
Think about Kashan the temporary file in which the information about the same requests to the same address
is kept for some time.
Time to leave is needed for us not to get not a up to date information simultaneously with server side
coercion we have client side resolver coercion the client resolver resolver on Windows systems also
contains a cache mechanism which stores resolve IP addresses and also hosts file information on a local
drive.
When a client encounters a name that needs to be resolved into an IP address it checks its local cache
first before sending a request to its DNS server.
Here is an example of for client side resolver Cashen client requests and information from DNS server
gets the response and then keeps it in cache saves it can in cache and reads it from cache.
The second time it needs the same information.
So the second time it needs to do a request on the same information it requests cache directly and gets
information from cache directly.
But when time to leave is all we're of this cache information.
It again requests DNS server for fresh information and then the same process happens again.