The most essential DNS Interview Questions and Answers may be found here. These DNS Interview Questions and Answers can assist you in preparing for a networking job interview. Preparing for an interview that involves DNS may be difficult; however, by skimming through common questions, you get a basic idea of what the interviewer may ask. DNS interview questions revolve around the way Domain Name System works. Questions regarding what it is and the functions it provides are only basic questions that will be asked. But, knowing the right way to answer them is how you can ace the interview you are preparing for.
Common DNS Interview Questions And Sample Answers
- What is DNS?
DNS, also known as Domain Name System, links various domain names to the IP addresses of the websites they belong to. DNS converts an IP address to a domain name, making the full internet address simple to remember. Because IP addresses are used for every communication in any network, it is impossible to remember the IP addresses of all websites. People tend to visit websites using domain names rather than IP addresses since it’s more convenient to do so. For example, instead of using IP addresses to visit websites like “google.com” or “youtube.com,” DNS converts domain names to IP addresses and makes them available to humans.
- State the Different DNS Zones
As of now, there are said to be 3 DNS Zones:
- Primary Zone – A primary DNS zone is used to make numerous changes to the data. Updates to the primary DNS zone are performed through the authoritative DNS server for that primary zone.
- Secondary Zone – During zone transfer, a secondary DNS zone (also known as a read-only zone) is copied from the master server. A zone transfer can be used to update secondary zones.
- Stub Zone – The stub DNS zone was added to Windows Server 2003 as a new functionality. This zone simply contains the resources and records required to identify the master zone’s authoritative DNS servers.
- How does a DNS server function on the internet?
On the internet, a DNS server is a computer system that stores a database of public IP addresses and their domain names. As asked, the DNS server resolves or translates IP addresses into hostnames. DNS Servers are mostly used to locate and provide webpages to end-users through the Internet or a private network. It is always online or linked to a network. DNS servers use proprietary software and communicate with one another using proprietary protocols.
- What does a caching-only server do?
DNS servers that simply process name resolution queries, cache the responses, and deliver the results to the user are known as caching-only servers. When a query is cached, the request is handled locally rather than traveling to the real site the very next time it is made. The queries are handled more quickly by the caching-only server.
- How does the DNS Lookup Process operate, and what steps are involved?
If we take the case of DNS requests for a website, we can break down the process into the steps outlined below:
- When you put a website’s URL, such as youtube.com, into a web browser and then request that it be sent to a DNS recursive resolver through your ISP.
- The query is then to be sent by this DNS recursive resolver (.) to a DNS root nameserver as quickly as possible.
- The root DNS server reacts to the DNS resolver with the IP address of a Top-Level Domain (TLD) DNS server that has the domain information.
- After that, the DNS resolver looks up the.com Top Level Domain (TLD).
- The Top Level Domain server returns the IP address of the domain name servers.
- Finally, the DNS resolver comes into contact with the website’s name-server.
- The IP address for youtube.com is returned by the domain name server to the resolver.
- The DNS recursive resolver then sends the IP address of the domain requested to the web browser.
- What does an authoritative DNS server do?
A DNS server that first contains DNS records and resources is known as the authoritative server. This server is after the DNS lookup chain and will respond with the resource record that was requested. Finally, an authoritative DNS server allows a web browser to reach the IP address needed to visit a website.
- Why do people like to use DNS?
- DNS (Domain Name System) is used to search for websites’ locations on the net.
- DNS assigns a unique IP address to each web page and uses it to identify it.
- The Domain Name System (DNS) allows users to remember the name rather than the IP address and visit the website using the name.
- How does DNS spoofing work?
DNS spoofing is an exploit in which an attacker modifies DNS records and redirects online traffic to a false website that seems similar to the original. Once the user arrives, it may prompt them to enter into their account (which seems to be their website), providing the hacker the opportunity to steal their login credentials and other important information. These harmful websites are frequently used to transmit infections on a user’s computer while also providing the hacker with long-term access to the computer.
- What’s the Difference Between Recursive and Authoritative DNS?
DNS record information is stored by authoritative name servers, which are generally DNS hosting providers or domain registrars. Between authoritative servers and end-users, recursive name servers act as “middlemen” because they must reach the name servers by recursing up the DNS tree since they are responsible for keeping the domain’s records.
- What role does DNS play in Active Directory?
The Domain Name System (DNS) is at the heart of Internet name resolution. You can simply establish DNS in an Active Directory environment, as well as name resolution for your customers. AD may extend DNS’s conventional feature set and add additional capabilities such as AD-Integrated DNS. An alternative DNS system, such as Unix BIND, can be easily adapted to Active Directory.
- What various sorts of DNS Queries are there?
The DNS client requests name-server information, which is known as a DNS query. The many forms of DNS requests are as follows:
- Recursion Query
- Iteration Query
- Non-Recursive query
- What is TTL and how long should your DNS TTL be?
“Time to Live” is abbreviated as TTL. The DNS TTL specifies how long a resolver should cache a DNS query for each DNS record given before it expires and a new one is needed. If you don’t need to make DNS updates, a TTL of 24 hours is usually sufficient. If you’re going to modify DNS records, however, you should specify a lower TTL value of 1 to 5 minutes at least 24 hours ahead of time.
- How does Recursive DNS RESOLVER work?
The recursive DNS RESOLVER is a middle server that obtains the domain’s IP address from authoritative DNS servers. Any DNS query sent to the internet is routed through the Recursive DNS RESOLVER. The Recursive server spends time tracking down DNS records when a client requests a DNS query after gathering the necessary data.
- In DNS, how many look-up zones are there?
There are two lookup zones in DNS:
- Forward Lookup Zone: Converts a domain name to an IP address. In the forward-lookup zone, an A-record is created.
- Reverse Lookup Zone: aids in the conversion of an IP address (10.251.87.121) to a domain name (w7cloud.com). In the Reverse Lookup Zone, a PTR record is created.
Bottom Line
This article on DNS Interview Questions aims to help you understand the essential concepts of DNS (Domain Name System) to prepare for an interview. For your convenience, all of the main DNS questions are covered in-depth with examples.
FAQs
- Which level of the DNS database contains a read/write copy?
The read-write copies of the hostname database and address information for an entire domain are maintained by one DNS name server in each administrative zone. This name server serves as the principal name server, and the domain administrator keeps it up to date with new hostnames and addresses. - State an example of a DNS zone.
A DNS zone is a portion of the DNS namespace that is controlled by a single entity or administrator. A DNS zone is a small administrative area for DNS components like authorized nameservers. The DNS root domain is at the top of a hierarchical tree that makes up the domain namespace. - Should people use DNS?
DNS servers are responsible for creating IP addresses from domain names so machines can understand them. You’re most likely utilizing a DNS server provided by your ISP, the quality of which is unknown. Switching to a third-party DNS service can improve your internet experience while also protecting you from DNS-based assaults. - Is it risky to change DNS?
Switching from your existing DNS server to a different one is completely safe and will have no negative consequences for your computer or device. It might be that the DNS server doesn’t provide you with adequate features, such as privacy, parental controls, and high redundancy, that some of the finest DNS public/private servers do.