Why Does Adding a Cloned Workstation Break Both Hosts' Network Access?

220-1201 By islever Editorial Last updated

Explain common network configuration concepts

Short answer

A The new workstation reused the other host's static IP configuration, creating a duplicate IP address that breaks connectivity for both machines.

Question

A support technician receives a call stating that a user has added a device to the network. The user used the same configurations from another workstation. When both workstations are turned on, neither can access the network reliably. Which of the following is the most likely cause of the issue?
  1. The new computer has a duplicate IP address. Correct Answer
  2. The DNS server is registering both hostnames.
  3. The network cable was improperly terminated
  4. The security on the switchport needs to be reset.

Key Takeaways

Tests whether you can trace a "same configuration copied from another workstation" symptom to an IP address conflict, rather than blaming the physical layer or DNS.

When a new device is configured with an exact copy of another workstation's settings, both machines end up with the same static IP address and fight over it on the LAN. This page confirms that a duplicate IP address (A) — not DNS, cabling, or switchport security — explains why neither host can reach the network reliably.

Common mistake: Choosing the improperly terminated network cable (C), because cabling problems feel physical and obvious, even though a bad termination would affect only one host and would not appear the moment the second workstation is powered on.

Expert Analysis

Why the Answer Is Correct

Copying "the same configurations from another workstation" means the second machine received the same static IPv4 address, subnet mask, and gateway as the first. Two hosts answering ARP for one address produce exactly the described symptom: whichever machine answers last wins the traffic, so both lose reliable connectivity while they are powered on together, and the behavior disappears when one is switched off. Modern operating systems also raise a duplicate-address-detection warning or log an IP conflict event, which is the fastest confirmation a technician can look for. This is a classic network configuration concept tested in the SOHO/configuration domain: a static address must be unique within the subnet.

Why the Other Options Are Wrong

DNS registering both hostnames (B) is a name-resolution event, not a connectivity event — duplicate or additional A records do not knock hosts off the network, and reverse registration issues do not produce the on/off pattern tied to the second machine being powered up. An improperly terminated cable (C) is a physical-layer fault that would degrade or drop the link for one specific workstation only; it cannot be triggered by turning on a different computer, and it would typically show CRC/link errors rather than an intermittent shared failure. Switchport security (D) usually err-disables or restricts a port entirely when a violation occurs, producing a hard loss of connectivity on that port, not the mutual, intermittent unreliability described here.

Community Comment Notes

Multiple learners converge on option A, with one summarizing the logic as "same configurations = same ips = dup ip address" — the exact reasoning chain the exam expects. Another commenter notes the practical preventive control, keeping an IP address spreadsheet so static assignments are never reused by accident, which is a good operational takeaway to remember. A third commenter states it was "confirmed to be answer A", and the overall discussion treats DNS, cabling, and switchport security as distractors rather than plausible causes.

Exam Strategy

When a stem says a device was set up with "the same configurations" as an existing host and both then misbehave together, treat it as an addressing conflict before anything else. Eliminate any option that could only explain a single-host failure (cable, switchport) or a name-resolution issue (DNS).

Frequently Asked Questions

Why does a duplicate IP address break connectivity for both workstations, not just the new one?

Both hosts answer ARP for the same address, so switches and peers send traffic to whichever machine replied last, causing intermittent loss for each of them.

Why is the improperly terminated network cable not the likely cause here?

A cabling fault affects only the host on that cable, whereas this failure appears only when the second workstation is powered on — the signature of an address conflict.

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Discussion 5 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 5

  1. dddba0a 👍 3 Answered A
    same configurations = same ips = dup ip address
  2. ishan94 👍 2 Answered A
    The user used the same configurations from another workstation
  3. ROTHERMEL01 👍 2 Answered A
    It was confirmed to be answer A
  4. 351199f 👍 1 Answered A
    A. The new computer has a duplicate IP address. Duplicate IPs always screw with computers on the same network. If you're ever going to use static IPs, make sure to have some sort of IP sheet to know what machines are using what to avoid this situation all together.
  5. acf9805 👍 1 Answered A
    41. A — Duplicate IP address 🧸 Two computers were given the same address → network says, “Which one of you is this?!” 😵

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