Top 30 Windows Server Dns Interview Questions You Must Prepare 19.Mar.2024

We use the following commands for DNS:

  • Nslookup (and all interactive mode commands)
  • Ipconfig /fulshdns
  • Ipconfig /registerdns

The default settings are

  • To Refresh interval 10 minutes
  • To Retry interval, 15 minutes
  • To Expire after 1 day

Forward lookup resolves the Hostnames (Friendly Name) to IP addresses.

Domain properties contain the following tabs:

  • General
  • Start of Authority (SOA)
  • Named servers
  • WINS
  • Zone transfers

The process of translating the name into some object or information that the name represents is called name resolution. A telephone book forms a namespace in which the names of telephone subscribers can be resolved to the phone numbers.

(Open DNS console ==> Right click on Domain name ==> Click on forwarder tab)

A forwarder is server, which has more access than the present DNS server. May be our present DNS server is located in internal network and it cannot resolve the Internet names. Maybe it is behind a firewall or maybe it is using a proxy server or NAT server to get to the Internet. Then this server forwards the query to another DNS server that can resolve the Internet names.

Command prompt commands:

  • Type Nslookup to get into the Nslookup mode.
  • Type set type=SOA then press enter type domain name
  • Type set type=NS then press enter; and type domain name.
  • Type set type=ALL then press enter.

Note: To come out from Nslookup mode type exit.

The structure of DNS starts with root domain. Then it (root domain) braches to TOP level domains, then second level domains, and so on to the individual host names.

 Root Domain –> Top level Domains–> Second level Domains–> So on so forth up to individual host systems

  • If you want to create an Active Directory integrated zone, the server must be Domain Controller.
  • If you want to create the Primary DNS, you can create on Domain Controller or Member server. But if create on member you could not get 4 options under the domain which are meant for Active directory.
  • You can create Secondary zone on a Member Server or on a Domain Controller. There is no difference between them.

DNS stands for Domain Name System. It is a hierarchical system for identifying hosts on the Internet or on a private, corporate TCP/IP internetwork. It resolves the IP addresses to host names (or friendly internet names) and Host names to IP addresses.

To get them back, simply just stop and start the netlogon service.

Type the following commands to stop and start the net logon service:

  • Net stop netlogon
  • Net start netlogon

Whenever you create a root zone (i.e., “.”) in a DNS server, the forwards, and root hints tabs will be disabled on that DNS server.

Right Click on any zone –>properties –>on General tab u will get

Allow Dynamic Updates? [_Yes/No/Secure Updates]

Note: Put always Dynamic Updates “YES”

Note: If it is Active Directory Integrated zone you will get above three options.

But if it is Primary or Secondary zone you will get only “YES/NO” (You won’t get secure updates)

We can install DNS in 3 different ways:

  • While installing Operating System: While installing Operating System, It asks at Network Settings whether you want Typical settings or Custom Settings. Select Custom Settings–>Select Network Services–>click on Details–>Select DNS–>ok
  • While installing through Active Directory (DCPROMO): (During installation it asks for CD)
  • Independently: Programs –>Settings –>Control Panel –Add/Remove Programs –>Add/Remove Windows Components –>Select the Network Services–>Click on properties –>Select DNS –>OK (During the installation it asks for CD)

  • Just install the DNS service into your windows 2000 server. Then it is called caching only DNS server, because it starts working for your clients to resolve the Internet names to IP address.
  • When you are installing DNS service at that time it is preconfigured with root DNS servers IP addresses.
  • If anybody wants to resolve the records that belong to your domain then you need to configure your DNS server appropriately.

Start–>Programs–>Administrative Tools–>DNS

Or

Start–>Run–>dnsmgmt.msc

Or

Start–>Run –>cmd –>dnsmgmt.msc

  • Primary zone has read and write permissions, whereas Secondary zone has read only permission.
  • Secondary zone is used for Backup and Load balancing.

PTR record is created in Reverse lookup zone. It is the record to main database for reverse lookup zone purposes (to convert from IP address to host names). Each host record in forward lookup should have an associated pointer record in reverse lookup zone.

Generally first you will create a Forward lookup zone. Then go for Reverse lookup zone. Now we have to create associated pointer records for host records in forward lookup zone. If you are creating a host record in forward lookup zone after creating reverse lookup zone then here we need not to create a pointer record by coming to reverse lookup zone. When creating new host, click on the check box of create associated pointer record. Then it automatically creates associated pointer record in reverse lookup zone.

The most general records found in DNS database are

  • Host Record (A record)
  • Mail Exchange Record (MX record)
  • Canonical name or CNAME record (CNAME)

Generally we need to create a host record for newly joined computer (either client or Member server or Domain controller). If you enable dynamic Update option, then DNS itself creates associated host record for newly joined computers.

Reverse lookup resolves the IP addresses to Host names.

Your DNS server requests the root level DNS server for specific IP address. Now DNS server says I don’t know but I can give the address other person who can help you in finding IP address.

Microsoft suggests that we use Windows 2000 DNS server. If you want to get 100% functionality you have to use 2000 DNS server. But you can also use BIND (Berkeley internet name domain) DNS servers, but if you want you use with Windows 2000 you should have at least Bind version 4.9.@(Previous versions don’t support SRV records)

Server properties contain the following tabs:

  • Interface
  • Forwarders
  • Advanced
  • Root hints
  • Logging
  • Monitoring

First go to primary zone check primary zone is working or not.

IF primary zone is working then go to secondary zone, Right click on zone name select the “Transfer from Master” then it automatically contacts the primary DNS, if any updates are there then it takes the updates from the Primary.

No, we cannot have two primary DNS zones. Why because if u have two primary DNS zones some clients contacts first one, some clients contacts second one according to their configuration in TCP/IP properties. Then you will get problems. Actually Primary DNS zone means Single master. i.e., master is only one that is only one primary DNS zone. But you can have as many as Secondary zones.

To overcome from above problem (i.e., single master problem) in Windows 2000 we have Active Directory Integrated zones, which are multi masters.

In order to check whether a DNS is working or not, type the command “nslookup” in command prompt. It will give the DNS server name and its IP address.

The query that has been sent to the DNS server from a Client is called iterative query.
(i. e., iterative query is nothing but gives the answer for my question, don’t ask to contact that person or this person or don’t say something else. Simply just answer to my question. That’s all)

  • Click on the Pause button.
  • Click on General tab
  • Go to properties of a zone

Note: When you install a Windows 2000 DNS server, you immediately get all of the records of root DNS servers. So every windows 2000 DNS server installed on Internet has pre configured with the address of root DNS servers. So every single DNS server in the Internet can get root servers.

  • Compare the Serial Number on Start of Authority tab in both secondary on primary DNS zone properties.
  • If both are same then recent updates are made to secondary zone.
  • If not (i.e., secondary is less then primary) click on “Transfer from Master”

Also called a zone of authority, zone is a subset of the Domain Name System (DNS) namespace that is managed by a name server. A database of records is called a zone.

Open the DNS Console. Then you will find there

  • DNS
  • Server name
  • Forward Lookup Zone
  • Reverse Lookup Zone

Note: If you have selected create automatically zones during the setup, then it creates the root zone and domain zone under forward lookup zone. If no zones are there under forward lookup zone first create root zone then create domain zone.