DNS Server Interview Questions and answers

1) Types of DNS Servers

Primary DNS

Secondary DNS

Active Directory Integrated DNS

Forwarder

Caching only DNS

2) What is the main purpose of a DNS server?
DNS servers are used to resolve FQDN hostnames into IP addresses and vice versa.

3) What is the port no of dns ?
53.

4) What is a Forward Lookup?
Resolving Host Names to IP Addresses.

5) What is Reverse Lookup?
It?s a file contains host names to IP mapping information.

6) What is a Resource Record?
It is a record provides the information about the resources available in the N/W infrastructure.

7) What are the DNS Roles?
Standard Primary, Standard Secondary, & AD Integrated.

8) What is a Zone?
Zone is a sub tree of DNS database.

9) Types of DNS Servers?

Primary DNS

Secondary DNS

Active Directory Integrated DNS

Forwarder

Caching only DNS

10)  Types of DNS Zone ?

Primary Zone

Secondary Zone

AD integrated Zone

Stub Zone

11) How many SOA record does each zone contain?

Each zone will have one SOA record. 

12) What is DDNS?

Ans: It dynamically registers m/c name in the AD integrated DNS database. It also used to dynamically register domain controllers name in the DNS at the time of installing AD.

13) What are Resource records in DNS?

 RR in DNS are MX, PTR, A, SOA, SRV, CNAME, NS.

14) What are SRV records?

These are the records which maps the AD service with the location of the service i.e. GC, Kerberos and LDAP

15) What is the main purpose of SRV records ?
SRV records are used in locating hosts that provide certain network services.

16) What is SOA Record?

SOA is a Start Of Authority record, which is a first record in DNS, which controls the startup behavior of DNS. We can configure TTL, refresh, and retry intervals in this record.

17) What are the types of DNS?

Primary, Secondary, Catch only.

18) What are different DNS queries?

Recursive and iterative.

 19) What is primary and secondary  Zones in DNS?

DNS servers can contain primary and secondary zones. 

Primary zone is a copy of a zone where updates can be made,

Secondary zone is a copy of a primary zone.  For fault tolerance purposes and load balancing, a domain may have several DNS servers that respond to requests for the same information.

The entries within a zone give the DNS server the information it needs to satisfy requests from other computers or DNS servers.

20) What is an AD-integrated zone?

AD-integrated zones store the zone data in Active Directory and use the same replication process used to replicate other data between domain controllers.

The one catch with AD-integrated zones is that the DNS server must also be a domain controller.

21) What is a STUB zone?

A stub zone is a copy of a zone that contains only those resource records necessary to identify the authoritative Domain Name System (DNS) servers for that zone.

A stub zone is used to resolve names between separate DNS namespaces.

The master servers for a stub zone are one or more DNS servers authoritative for the child zone

22) What is NSlookup ?

It is a tool used troubleshoot DNS related issues.

23) How do you manually create SRV records in DNS?
This is on windows server go to run ---> dnsmgmt.msc rightclick on the zone you want to add srv record to and choose "other new record" and choose service location(srv).

24) Where does a Host File Reside?
c:\windows\system32\drivers\etc.

25) What is a query?
A request made by the DNS client to provide the name server information.

26) What are the diff. types of Queries?
Recursion, iteration.

27) Tools for troubleshooting DNS?
DNS Console, NSLOOKUP, DNSCMD, IPCONFIG, Logs.