All 149 questions

  1. What is DHCP?

    Asked in 6 of 337 interviews · last asked Oct 21 · Concept · Junior

    Show answer

    DHCP stands for Dynamic Host Configuration Protocol. It automatically gives devices an IP address and other network settings, such as a subnet mask, default gateway, and DNS servers. IP addresses are usually leased for a limited time and can be renewed.

    • DHCP reduces manual setup and mistakes in network settings.
    • DHCPv4 typically uses four steps: Discover, Offer, Request, and Acknowledge.
    • DHCPv4 uses UDP port 67 on the server and port 68 on the client.

    What the interviewer checks: The interviewer is checking whether you understand how devices automatically receive their network settings.

    Other ways it was asked
    • “Could you explain DHCP?”
    • “What can you tell me about DHCP?”
    • “What is the meaning of DHCP?”

  2. What is the difference between a dynamic IP address and a static IP address?

    Asked in 4 of 337 interviews · last asked Sep 24 · Concept · Junior

    Show answer

    A static IP address stays fixed until someone changes its configuration. A dynamic IP address is assigned automatically, usually by DHCP, and may change over time. Static addresses help devices stay reachable at a known address, while dynamic addresses reduce manual setup.

    • DHCP-assigned addresses use leases; renewing a lease does not always change the address.
    • Static addresses are useful for servers and other devices that need predictable addresses.
    • A DHCP reservation can give a device the same address automatically.

    What the interviewer checks: The interviewer is checking whether you understand address stability, DHCP assignment, and when each type is useful.

    Other ways it was asked
    • “What is the difference between a static and a dynamic IP address?”
    • “What is the difference between a static and dynamic IP address?”

  3. Can you describe DNS?

    Asked in 4 of 337 interviews · last asked Oct 21 · Concept · Junior

    Show answer

    DNS stands for Domain Name System. It translates domain names, such as example.com, into IP addresses that computers use to connect. It is a distributed, hierarchical system that also stores records for services such as email. DNS resolvers look up records and cache them to speed up later requests.

    • DNS uses a hierarchy of root servers, top-level domain servers, and authoritative servers.
    • A records hold IPv4 addresses; AAAA records hold IPv6 addresses; MX records identify mail servers.
    • Cached records have a time to live, or TTL, which limits how long they remain valid.
    • DNS commonly uses UDP port 53, but also uses TCP port 53.

    What the interviewer checks: The interviewer is checking whether you understand name resolution, the DNS hierarchy, and caching.

    Other ways it was asked
    • “What is DNS?”
    • “What can you tell me about DNS?”

  4. What are the IPv4 address classes?

    Asked in 3 of 337 interviews · last asked Sep 24 · Concept · Junior

    Show answer

    IPv4 has five historical address classes, based on the first octet: A (0–127), B (128–191), C (192–223), D (224–239), and E (240–255). Classes A, B, and C were for unicast addressing; D is for multicast, and E is reserved. Modern networks use CIDR instead of classes.

    • Default masks were A: 255.0.0.0 (/8), B: 255.255.0.0 (/16), and C: 255.255.255.0 (/24).
    • Class A’s usual first-octet range is 1–126; 0 has special uses, and 127 is for loopback.
    • 255.255.255.255 is the limited broadcast address, an exception within the Class E range.
    • CIDR uses a prefix length to define the network boundary, rather than an address class.

    What the interviewer checks: The interviewer checks whether you know the class ranges, their uses, and how CIDR replaced class-based addressing.

    Other ways it was asked
    • “What are the different IPv4 address classes, and what are their ranges?”
    • “How many IPv4 address classes are there?”
    • “Which IPv4 address classes are there?”

  5. What port does DNS use?

    Asked in 3 of 337 interviews · last asked Oct 19 · Concept · Junior

    Other ways it was asked
    • “Which communication protocol does DNS use, and on which port?”
    • “What is the port number of DNS?”

  6. Why do we need IPv6 when we are currently using IPv4, and what is the difference between IPv4 and IPv6?

    Asked in 2 of 337 interviews · last asked Aug 12 · Concept · Junior

    Other ways it was asked
    • “What's the difference between IPv4 and IPv6?”

  7. Why does DNS use TCP in some cases instead of UDP?

    Asked in 2 of 337 interviews · last asked Sep 10 · Concept · Mid-level

    Other ways it was asked
    • “When does DNS use TCP?”

  8. What is the default gateway?

    Asked in 2 of 337 interviews · last asked Sep 19 · Concept · Junior

    Other ways it was asked
    • “What is the default gateway for a network?”

  9. Can you explain the difference between DHCP and DNS?

    Asked in 2 of 337 interviews · last asked Oct 21 · Concept · Junior

    Other ways it was asked
    • “What is the relationship between DHCP and DNS?”

  10. What are network and broadcast addresses in an IPv4 subnet, and what purpose does each serve?

    Asked in 2 of 337 interviews · last asked May 7 · Concept · Junior

    Other ways it was asked
    • “What is a broadcast address in IPv4 subnetting?”

  11. What happens when a Windows machine starts up and obtains an IP address through DHCP?

    Asked once · last asked Sep 30 · Concept · Mid-level

    Other ways it was asked
    • “After a Windows machine obtains an IP address through DHCP, what other steps typically occur during startup?”

  12. When you enter google.com in a browser, how does the DNS client resolve the name to an IP address?

    Asked once · last asked Feb 24 · Concept · Junior

  13. In a corporate environment, what happens when an internal DNS server cannot resolve a query?

    Asked once · last asked Feb 24 · Scenario · Mid-level

  14. When an internal DNS server cannot resolve a query, which server should it forward the query to?

    Asked once · last asked Feb 24 · Concept · Mid-level

  15. If a recursive DNS resolver cannot find an answer, where does it send the query next?

    Asked once · last asked Feb 24 · Concept · Mid-level

  16. After a DNS query reaches a top-level domain server, where does it go next?

    Asked once · last asked Feb 24 · Concept · Junior

  17. What is the difference between primary, secondary, and stub DNS zones?

    Asked once · last asked Feb 24 · Concept · Mid-level

  18. What is the difference between an iterative DNS query and a recursive DNS query?

    Asked once · last asked Feb 24 · Concept · Mid-level

    Other ways it was asked
    • “What is the difference between an iterative query and a recursive query?”

  19. What can you tell me about DNS aging and scavenging?

    Asked once · last asked Feb 24 · Concept · Mid-level

  20. What is one benefit of integrating DNS with Active Directory?

    Asked once · last asked Feb 24 · Concept · Mid-level

  21. A new laptop has never been on the network before. When it is connected to Ethernet, how does it obtain an IP address?

    Asked once · last asked Feb 24 · Scenario · Junior

  22. If a DHCP server cannot be reached, can a client still obtain an IP address?

    Asked once · last asked Feb 24 · Scenario · Mid-level

  23. When does a DHCP client attempt to renew its lease?

    Asked once · last asked Feb 24 · Concept · Mid-level

    Other ways it was asked
    • “What happens if a DHCP client's lease renewal attempt fails at the 50% point?”

  24. How can DHCP consistently assign the same IP address to a client?

    Asked once · last asked Feb 24 · Concept · Mid-level

  25. How can a DHCP client and server on different subnets communicate so the client can obtain an IP address?

    Asked once · last asked Feb 24 · Scenario · Mid-level

  26. With multiple subnets and DHCP relay agents, how does the DHCP server determine which scope to use for a client?

    Asked once · last asked Feb 24 · Scenario · Mid-level

  27. What is a DHCP scope, and how many types are there?

    Asked once · last asked Feb 24 · Concept · Mid-level

    Other ways it was asked
    • “What is the difference between the types of DHCP scopes?”

  28. What is DHCP failover?

    Asked once · last asked Feb 24 · Concept · Mid-level

  29. What DHCP scope configuration issues can prevent clients from receiving IP addresses?

    Asked once · last asked Feb 25 · Scenario · Mid-level

  30. What are the key concepts involved in DNS, and how do they affect name resolution?

    Asked once · last asked Mar 9 · Concept · Mid-level

  31. How does public NAT work, and when would you use it?

    Asked once · last asked Apr 6 · Concept · Mid-level

  32. What IP address conflicts can occur if an old switch remains connected, and how would you diagnose them?

    Asked once · last asked Apr 7 · Scenario · Mid-level

  33. Two PCs connected to the same switch have IP addresses 192.168.1.1/24 and 192.168.1.2/24. If you ping from PC 1 to PC 2, will it work? If so, explain the packet-level process.

    Asked once · last asked Apr 13 · Scenario · Junior

  34. Can two PCs on different subnets, 192.168.1.0/24 and 192.168.2.0/24, ping each other, and what network configuration is required?

    Asked once · last asked Apr 13 · Scenario · Junior

  35. What DNS configuration, including conditional forwarding, is needed to keep a private AKS cluster reachable if its IP changes after a restart?

    Asked once · last asked Apr 14 · Scenario · Senior

  36. What command would you use on a Windows 10 computer to display the subnet mask?

    Asked once · last asked Apr 15 · Tooling · Junior

  37. How do you use Infoblox for DNS and IPAM tasks such as assigning IP addresses to requested subnets or VLANs, creating host records and subnets, and adding domain and CNAME records?

    Asked once · last asked Apr 23 · Tooling · Mid-level

  38. Could you briefly walk me through how DNS resolution works, starting from your local PC?

    Asked once · last asked Apr 24 · Concept · Junior

  39. What happens when a DNS record is not found in the local cache?

    Asked once · last asked Apr 24 · Concept · Junior

  40. A DNS record has been updated to point to a new server, but the browser still shows the old content. What could cause this, and how would you resolve it?

    Asked once · last asked Apr 24 · Scenario · Mid-level

  41. Які параметри DHCP-сервер надає комп’ютеру?

    Asked once · last asked May 8 · Concept · Junior

  42. How does a DHCP server identify a device when assigning network settings, and what unique identifier does each network device have?

    Asked once · last asked May 8 · Concept · Junior

  43. Can two laptops with IP addresses in the same subnet communicate if no gateway is configured?

    Asked once · last asked May 8 · Scenario · Junior

  44. What is the key difference between a LAN and a subnet?

    Asked once · last asked May 8 · Concept · Junior

  45. Which IPv4 header option requires a datagram to follow exactly the route specified by a sequence of IP addresses?

    Asked once · last asked May 11 · Concept · Junior

  46. Which technology allows IP addresses to be allocated without fixed address classes, helping conserve address space?

    Asked once · last asked May 11 · Concept · Junior

  47. How would you configure DHCP or DNS?

    Asked once · last asked May 12 · Tooling · Mid-level

  48. What is a CNAME record in DNS?

    Asked once · last asked May 12 · Concept · Junior

  49. What is the difference between an MX record and an A record?

    Asked once · last asked May 13 · Concept · Junior

  50. Describe a complex Route 53 scenario and how you would resolve it.

    Asked once · last asked Jun 11 · Scenario · Senior

  51. What is the difference between a conditional forwarder and a stub zone?

    Asked once · last asked Jul 16 · Concept · Mid-level

  52. How is an ARP request sent if the host does not know the gateway's MAC address?

    Asked once · last asked Aug 4 · Concept · Mid-level

  53. Can you walk through the DNS resolution process in detail?

    Asked once · last asked Aug 4 · Concept · Mid-level

  54. What is the difference between DNS and DHCP, and how could problems with each affect a user's connection?

    Asked once · last asked Aug 9 · Concept · Junior

  55. Can you explain at a high level NAT, network address translation, and how you would implement it?

    Asked once · last asked Aug 19 · Concept · Mid-level

  56. Why is DNS critical for Active Directory?

    Asked once · last asked Aug 21 · Concept · Mid-level

  57. What are SRV records in DNS?

    Asked once · last asked Aug 21 · Concept · Mid-level

  58. When you suspect DNS is the root cause of the issue, how do you validate name resolution and domain controller discovery?

    Asked once · last asked Aug 24 · Scenario · Mid-level

  59. A user can browse websites by IP address but not by hostname on a Windows machine. What is your step-by-step troubleshooting approach?

    Asked once · last asked Aug 24 · Scenario · Mid-level

    Other ways it was asked
    • “A user can browse websites by IP address but not by host name on a Windows machine. What's your troubleshooting step-by-step?”

  60. A user connects to the corporate VPN, gets an IP, but cannot reach any internal DNS names while public internet works. What would you check first on the client and VPN side?

    Asked once · last asked Aug 24 · Scenario · Mid-level

  61. If a hostname has different records in local and public DNS, which result does the browser use?

    Asked once · last asked Aug 25 · Concept · Mid-level

  62. How do you handle resource pool allocation and IP address management?

    Asked once · last asked Aug 30 · Scenario · Senior

  63. Explain weighted, latency-based, failover, and geolocation routing.

    Asked once · last asked Aug 30 · Concept · Mid-level

  64. What is the difference between simple and weighted routing policies in Route 53?

    Asked once · last asked Aug 31 · Concept · Mid-level

  65. After a domain migration, some machines still hit old domain controllers. What's a common cause?

    Asked once · last asked Sep 1 · Scenario · Mid-level

  66. DNS queries succeed, but some responses intermittently return SERVFAIL. What might cause that?

    Asked once · last asked Sep 1 · Scenario · Mid-level

  67. You flush the DNS cache, but name resolution issues come back. What does that suggest?

    Asked once · last asked Sep 1 · Scenario · Mid-level

  68. If only VPN users report DNS issues, what would you check?

    Asked once · last asked Sep 1 · Scenario · Mid-level

  69. If you see that DNS queries leave but replies don't always return, what's the likely culprit?

    Asked once · last asked Sep 1 · Scenario · Mid-level

  70. How would you flush the DNS cache on a user's computer when they cannot log in?

    Asked once · last asked Sep 2 · Tooling · Junior

  71. How do you test whether the DNS servers are working?

    Asked once · last asked Sep 2 · Tooling · Mid-level

  72. How do you force the machine to use the other DNS server?

    Asked once · last asked Sep 2 · Tooling · Mid-level

  73. If the default gateway pings successfully but DNS lookups fail for all domains, what would you check next to decide whether it’s a DNS-to-client issue or upstream DNS reachability?

    Asked once · last asked Sep 2 · Scenario · Mid-level

  74. What is DNS and how does it work under the covers?

    Asked once · last asked Sep 8 · Concept · Mid-level

  75. What other network configuration information can DHCP provide besides an IP address?

    Asked once · last asked Sep 8 · Concept · Junior

  76. Where would you place DNS and DHCP services in a network design?

    Asked once · last asked Sep 18 · Design · Mid-level

  77. Which private IPv4 address ranges are available for use?

    Asked once · last asked Sep 24 · Concept · Junior

  78. How would you assign a new IP address to a computer?

    Asked once · last asked Oct 5 · Tooling · Junior

  79. Suppose a user can't access a website because of a DNS problem; how would you troubleshoot it?

    Asked once · last asked Oct 8 · Scenario · Mid-level

  80. If a network interface has not received an IP address and you suspect a DHCP issue, how would you troubleshoot it?

    Asked once · last asked Oct 8 · Scenario · Mid-level

    Other ways it was asked
    • “If DHCP looks suspicious and the interface didn't get an IP, what would you do?”

  81. If the gateway ping is fine, but external DNS still fails, what's your next command, and what are you looking for?

    Asked once · last asked Oct 8 · Scenario · Mid-level

  82. How does DNS use A records, CNAME records, and MX records?

    Asked once · last asked Oct 8 · Concept · Junior

  83. How do you discover a website's IP addresses?

    Asked once · last asked Oct 13 · Tooling · Mid-level

    Other ways it was asked
    • “Which commands and methods would you use to discover a website's IP addresses?”

  84. Which command can you use to view a Windows computer's DHCP-assigned IP address and other network details?

    Asked once · last asked Oct 19 · Tooling · Junior

  85. How many total and usable host IP addresses does a /27 IPv4 subnet provide?

    Asked once · last asked Jan 29 · Concept · Junior

  86. What does VLSM stand for?

    Asked once · last asked Feb 19 · Concept · Junior

  87. What is the highest level in the DNS hierarchy?

    Asked once · last asked Feb 24 · Concept · Junior

  88. What are A records and CNAME records?

    Asked once · last asked Feb 24 · Concept · Junior

  89. Where are DNS records stored?

    Asked once · last asked Feb 24 · Concept · Junior

  90. How many types of zones can you have on a DNS server?

    Asked once · last asked Feb 24 · Concept · Junior

  91. What is a DNS query?

    Asked once · last asked Feb 24 · Concept · Junior

  92. How many types of DNS queries are there?

    Asked once · last asked Feb 24 · Concept · Junior

  93. What does the acronym DORA stand for in DHCP?

    Asked once · last asked Feb 24 · Concept · Junior

    Other ways it was asked
    • “What does the acronym DORA stand for?”

  94. Is an IP address assigned by DHCP permanent, or does it have a limited lease?

    Asked once · last asked Feb 24 · Concept · Junior

  95. What is the standard lease time for a DHCP server?

    Asked once · last asked Feb 24 · Concept · Junior

  96. Which communication protocol does DHCP use?

    Asked once · last asked Feb 24 · Concept · Junior

  97. What symptoms can indicate a DHCP issue?

    Asked once · last asked Feb 25 · Concept · Junior

  98. Why are IPv4 addresses beginning with 127 not used for ordinary host addressing?

    Asked once · last asked Feb 27 · Concept · Junior

    Other ways it was asked
    • “Why is 127 not included in any IP address class?”

  99. What is the purpose of an IP address?

    Asked once · last asked Apr 4 · Concept · Junior

  100. How do you determine the network ID from an IPv4 address and subnet mask?

    Asked once · last asked Apr 13 · Concept · Junior

  101. What is the difference between NAT and PAT?

    Asked once · last asked Apr 27 · Concept · Junior

    Other ways it was asked
    • “What is a use case for each of NAT and PAT?”

  102. Where would you use NAT? Give me one real-world example.

    Asked once · last asked Apr 27 · Concept · Junior

  103. If the subnet prefix is /25, how many usable hosts are there?

    Asked once · last asked May 7 · Concept · Junior

    Other ways it was asked
    • “Why are there 126 usable host addresses in a /25 subnet?”

  104. Does a /25 subnet have 7 host bits, giving 2^7 total addresses?

    Asked once · last asked May 7 · Concept · Junior

  105. How do you determine the broadcast address?

    Asked once · last asked May 7 · Concept · Junior

  106. How many addresses are reserved in an IPv4 subnet?

    Asked once · last asked May 7 · Concept · Junior

  107. Given a subnet address and prefix length, how do you calculate how many hosts it can support?

    Asked once · last asked May 7 · Concept · Junior

  108. Why are two addresses subtracted from the total when calculating usable hosts in an IPv4 subnet?

    Asked once · last asked May 7 · Concept · Junior

  109. What are an IP address, a subnet mask, and a gateway, and how do they differ?

    Asked once · last asked May 7 · Concept · Junior

  110. What is an IP address?

    Asked once · last asked May 8 · Concept · Junior

  111. What is a subnet mask?

    Asked once · last asked May 8 · Concept · Junior

  112. What are DNS servers?

    Asked once · last asked May 8 · Concept · Junior

  113. Why is the Domain Name System (DNS) needed?

    Asked once · last asked May 8 · Concept · Junior

  114. How would you explain DNS to someone without a technical background?

    Asked once · last asked May 8 · Concept · Junior

  115. How does the Internet Protocol (IP) deliver data from a source to a destination?

    Asked once · last asked May 11 · Concept · Junior

  116. How long is an IPv4 address?

    Asked once · last asked May 11 · Concept · Junior

  117. What is the IPv6 loopback address?

    Asked once · last asked May 11 · Concept · Junior

  118. How do you create a subdomain in cPanel?

    Asked once · last asked May 13 · Tooling · Junior

  119. How do you flush the DNS cache in Windows?

    Asked once · last asked Jun 26 · Tooling · Junior

  120. How does DNS resolve a domain name to an IP address?

    Asked once · last asked Jul 16 · Concept · Junior

  121. Do you know how DNS works?

    Asked once · last asked Jul 16 · Concept · Junior

  122. What is DNS, and what does a DNS error indicate?

    Asked once · last asked Jul 28 · Concept · Junior

  123. What information does the DHCP process provide to a client?

    Asked once · last asked Jul 31 · Concept · Junior

  124. What layer does IP addressing operate at, and what is the purpose of IP addressing?

    Asked once · last asked Aug 4 · Concept · Junior

  125. Can you give me an example of a Class A IP address?

    Asked once · last asked Aug 9 · Concept · Junior

  126. Does IPv6 use address classes like IPv4?

    Asked once · last asked Aug 9 · Concept · Junior

  127. Tell me different types of IP addresses.

    Asked once · last asked Aug 12 · Concept · Junior

  128. Who assigns IP addresses to devices on a network?

    Asked once · last asked Aug 12 · Concept · Junior

  129. What is NAT in networking?

    Asked once · last asked Dec 4 · Concept · Junior

  130. What is a static IP address?

    Asked once · last asked Dec 4 · Concept · Junior

  131. What is the difference between local DNS and global DNS? Give one example for each.

    Asked once · last asked Aug 18 · Concept · Mid-level

  132. What are DNS forwarders and what is their use?

    Asked once · last asked Aug 18 · Concept · Junior

  133. What DNS record types are available?

    Asked once · last asked Aug 18 · Concept · Junior

  134. What is CIDR notation?

    Asked once · last asked Aug 30 · Concept · Junior

  135. What would you look up with nslookup?

    Asked once · last asked Sep 2 · Tooling · Junior

  136. Why is DNS knowledge so important for this role?

    Asked once · last asked Sep 2 · Concept · Junior

  137. What are an IP address, subnet mask, default gateway, and DNS?

    Asked once · last asked Sep 3 · Concept · Junior

  138. Explain how DNS works in Linux.

    Asked once · last asked Dec 11 · Concept · Mid-level

  139. In DNS, what port does DNS run on, and why is it port 53?

    Asked once · last asked Sep 10 · Concept · Junior

  140. Which transport protocols can DNS use: UDP, TCP, or both?

    Asked once · last asked Sep 10 · Concept · Junior

  141. What is NAT, and what firewall operations use it?

    Asked once · last asked Sep 17 · Concept · Junior

  142. What are the benefits of implementing DNS and DHCP?

    Asked once · last asked Sep 18 · Concept · Junior

  143. How do you identify the top-level domain in a URL?

    Asked once · last asked Sep 23 · Concept · Junior

  144. What is the difference between a private IP address and a public IP address?

    Asked once · last asked Sep 24 · Concept · Junior

  145. What is a NAT gateway?

    Asked once · last asked Sep 25 · Concept · Junior

  146. What does TTL (time to live) mean in computing, and where is it used?

    Asked once · last asked Sep 28 · Concept · Junior

  147. How would you configure a subnet?

    Asked once · last asked Oct 16 · Scenario · Junior

  148. If you were given a subnet or IP address and told it needed to be a /24, what would that mean?

    Asked once · last asked Oct 16 · Concept · Junior

  149. What are the port numbers used by DHCP?

    Asked once · last asked Oct 19 · Concept · Junior

More Computer Networks interview questions

How this list is made

Every question here was asked by a real interviewer in a real job interview that a candidate ran MeetAssist in. After the call, the interviewer's questions are pulled from the transcript. Practice sessions, tests, exams and anything that was not a job interview are dropped.

Questions are rewritten so they make sense on their own: names of people, employers and clients are removed, and speech-to-text mistakes are fixed. Small talk, logistics and questions about one candidate's own résumé are left out. Rephrasings of the same question are merged, and the count is the number of different interviews it came up in.

The interviews come from candidates who use MeetAssist, so they lean towards software, data and AI roles: the shares describe these interviews, not every Computer Networks interview. Answers to the most asked questions are written and checked by an editor; a "common mistake" is shown only when reviews of real answers in these interviews show it, with the count.

337 interviews, 208 candidates, Nov 2025 to Oct 2026. Updated every month with new interviews.