ZorixOS
87+ Cisco questions

Cisco interview questions and how to prepare

The questions candidates report from Cisco interviews, sorted by how often they come up, with difficulty and topics, plus original practice written in Cisco's interview style.

Practice Cisco questions free All companies

ZorixOS tracks 87 community-reported Cisco interview questions, drawn from an open-source dataset of real interview reports and sorted by how frequently each one comes up. Every question links to its source. Alongside them are 78 original ZorixOS practice questions written in Cisco's known interview style (not claimed as asked at Cisco), so you can rehearse the real format. Practice any of them out loud in a free AI mock interview tuned to Cisco.

Updated July 2026

Cisco interview questions candidates report

Community-reported from real Cisco interviews (open-source dataset), most-asked first. Showing 60 of 87. Each links to its source.

  1. Implement Router
    ArrayHash TableBinary SearchDesign
    Medium100% asked
  2. Longest Palindromic Substring
    Two PointersStringDynamic Programming
    Medium100% asked
  3. Lucky Numbers in a Matrix
    ArrayMatrix
    Easy100% asked
  4. Predict the Winner
    ArrayMathDynamic ProgrammingRecursion
    Medium100% asked
  5. House Robber
    ArrayDynamic Programming
    Medium98% asked
  6. Rotate Image
    ArrayMathMatrix
    Medium85% asked
  7. Spiral Matrix
    ArrayMatrixSimulation
    Medium84% asked
  8. Fizz Buzz
    MathStringSimulation
    Easy77% asked
  9. Longest Substring Without Repeating Characters
    Hash TableStringSliding Window
    Medium72% asked
  10. Snakes and Ladders
    ArrayBreadth-First SearchMatrix
    Medium69% asked
  11. Find Third Transaction
    Database
    Medium67% asked
  12. LRU Cache
    Hash TableLinked ListDesignDoubly-Linked List
    Medium67% asked
  13. Number of Valid Words in a Sentence
    String
    Easy67% asked
  14. Max Points on a Line
    ArrayHash TableMathGeometry
    Hard65% asked
  15. Maximum Difference Between Increasing Elements
    Array
    Easy65% asked
  16. Merge Intervals
    ArraySorting
    Medium65% asked
  17. Linked List Cycle
    Hash TableLinked ListTwo Pointers
    Easy64% asked
  18. Maximum Subarray
    ArrayDivide and ConquerDynamic Programming
    Medium63% asked
  19. Word Search II
    ArrayStringBacktrackingTrie
    Hard63% asked
  20. Check if Binary String Has at Most One Segment of Ones
    String
    Easy63% asked
  21. Find the Largest Area of Square Inside Two Rectangles
    ArrayMathGeometry
    Medium63% asked
  22. Minimum Cost to Make Array Equal
    ArrayBinary SearchGreedySorting
    Hard63% asked
  23. Number of Equal Count Substrings
    Hash TableStringSliding WindowCounting
    Medium63% asked
  24. Sum of k-Mirror Numbers
    MathEnumeration
    Hard63% asked
  25. Happy Number
    Hash TableMathTwo Pointers
    Easy61% asked
  26. Stone Game
    ArrayMathDynamic ProgrammingGame Theory
    Medium61% asked
  27. Two Sum
    ArrayHash Table
    Easy59% asked
  28. Cherry Pickup
    ArrayDynamic ProgrammingMatrix
    Hard58% asked
  29. Valid Parentheses
    StringStack
    Easy58% asked
  30. Trapping Rain Water
    ArrayTwo PointersDynamic ProgrammingStack
    Hard56% asked
  31. Letter Combinations of a Phone Number
    Hash TableStringBacktracking
    Medium56% asked
  32. Meeting Rooms II
    ArrayTwo PointersGreedySorting
    Medium56% asked
  33. Merge Sorted Array
    ArrayTwo PointersSorting
    Easy56% asked
  34. Permutation in String
    Hash TableTwo PointersStringSliding Window
    Medium56% asked
  35. Remove Duplicates from Sorted Array
    ArrayTwo Pointers
    Easy56% asked
  36. Decode String
    StringStackRecursion
    Medium52% asked
  37. Remove Boxes
    ArrayDynamic ProgrammingMemoization
    Hard52% asked
  38. Best Time to Buy and Sell Stock
    ArrayDynamic Programming
    Easy50% asked
  39. Move Zeroes
    ArrayTwo Pointers
    Easy48% asked
  40. Number of Islands
    ArrayDepth-First SearchBreadth-First SearchUnion Find
    Medium48% asked
  41. Reverse Linked List
    Linked ListRecursion
    Easy48% asked
  42. Search a 2D Matrix
    ArrayBinary SearchMatrix
    Medium48% asked
  43. Strange Printer
    StringDynamic Programming
    Hard48% asked
  44. 3Sum
    ArrayTwo PointersSorting
    Medium45% asked
  45. Longest Consecutive Sequence
    ArrayHash TableUnion Find
    Medium45% asked
  46. Add Two Numbers
    Linked ListMathRecursion
    Medium42% asked
  47. Expressive Words
    ArrayTwo PointersString
    Medium42% asked
  48. Gas Station
    ArrayGreedy
    Medium42% asked
  49. Single Number
    ArrayBit Manipulation
    Easy42% asked
  50. Word Search
    ArrayStringBacktrackingDepth-First Search
    Medium42% asked
  51. Find Servers That Handled Most Number of Requests
    ArrayGreedyHeap (Priority Queue)Ordered Set
    Hard40% asked
  52. Group Anagrams
    ArrayHash TableStringSorting
    Medium40% asked
  53. Insert Delete GetRandom O(1)
    ArrayHash TableMathDesign
    Medium40% asked
  54. Merge k Sorted Lists
    Linked ListDivide and ConquerHeap (Priority Queue)Merge Sort
    Hard40% asked
  55. Top K Frequent Elements
    ArrayHash TableDivide and ConquerSorting
    Medium40% asked
  56. Valid Palindrome
    Two PointersString
    Easy40% asked
  57. Validate IP Address
    String
    Medium40% asked
  58. Beautiful Arrangement
    ArrayDynamic ProgrammingBacktrackingBit Manipulation
    Medium34% asked
  59. Climbing Stairs
    MathDynamic ProgrammingMemoization
    Easy34% asked
  60. Count of Integers
    MathStringDynamic Programming
    Hard34% asked

These are the 60 most-reported of 87 tracked Cisco questions. Create a free account to drill the full set with solutions and an AI interviewer.

Practice questions in Cisco's style

Original ZorixOS questions written the way Cisco interviews, so you rehearse the real format. Not claimed as asked at Cisco.

  1. Imagine you're optimizing a critical path in the Cisco Webex Meetings backend service that handles real-time audio/video streams for millions of concurrent users. Describe how you would approach diagnosing and resolving a potential latency issue that's causing intermittent audio glitches. Include specific tools and metrics you'd use, and outline a systematic debugging process.

    Software EngineerDebugging distributed systemsTests: Evaluates debugging skills in a high-scale, real-time distributed system.

  2. Design a system to automatically detect and mitigate DDoS attacks targeting Cisco Umbrella's DNS infrastructure. Consider the scale of requests, potential attack vectors, and the need for low-latency mitigation. What components would be involved, how would they interact, and what data would you monitor?

    Software EngineerSystem Design: Network SecurityTests: Assesses system design capabilities for network security at scale.

  3. A customer is reporting inconsistent performance with their Cisco Catalyst 9000 series switch in a large enterprise network. They suspect a configuration error but are unsure where to start. Outline a step-by-step approach to remotely troubleshoot this issue, focusing on data collection and analysis from the switch's CLI and potentially other network management tools.

    Software EngineerTroubleshooting network hardwareTests: Tests practical troubleshooting skills with enterprise networking hardware.

  4. Cisco is developing a new AI-powered feature for its ThousandEyes platform to predict network outages before they occur. Describe the technical challenges and potential approaches to building a reliable prediction model. How would you handle data drift, concept drift, and model explainability?

    Software EngineerMachine Learning System DesignTests: Evaluates understanding of ML system design challenges at enterprise scale.

  5. You're tasked with building a new API gateway for Cisco's internal microservices. Describe the key considerations for designing such a system, focusing on aspects like authentication, rate limiting, request routing, and observability. How would you ensure high availability and low latency?

    Software EngineerSystem Design: API GatewayTests: Assesses system design knowledge for scalable API infrastructure.

  6. Write a SQL query to find the top 5 customers by total bandwidth consumed on Cisco Meraki devices in the last month, joining data from a 'device_usage' table and a 'customer_info' table.

    Data ScientistSQL for Network Data AnalysisTests: Tests SQL proficiency for extracting business insights from network data.

72+ more Cisco-style questions are in the free library, each practiceable live with adaptive follow-ups and an honest scorecard. Start free.

Keep exploring

Can you answer these out loud, under Cisco-style follow-ups?

The ZorixOS AI interviewer runs a Cisco-tuned mock interview: it asks these kinds of questions, digs into your answers, and scores you against a real hiring bar. Your first one is free.

Start your Cisco mock interview
Cisco Interview Questions (2026) | ZorixOS