Network Doctor is a free, cross-platform terminal tool for finding where a network connection is failing. Its creator, Michael Placzek, said the project had earned $0 when he wrote about it on DEV Community; the excerpt available for that article does not establish its publication year, and that historical figure says nothing about current revenue.
The sustainability challenge is familiar to open-source developers: how do you ask people to fund useful software without making its useful features inaccessible? Network Doctor’s current options are voluntary sponsorship and a separate, paid diagnosis service.
What Network Doctor does
Network Doctor is a terminal-based troubleshooting tool for Linux, macOS, and Windows. Its central question is whether a connection problem is on the local network, somewhere along the route, or at the service. Rather than stopping at a basic connectivity check, it examines multiple layers, including interface and Wi-Fi status, internet egress, DNS, TCP, TLS, HTTP and HTTPS, proxies, and path MTU.
That breadth matters because a symptom such as “this site won’t load” can have many causes. A DNS lookup might fail while a connection to an IP address works; TCP may connect but TLS negotiation may not; an HTTP response may point to a problem beyond the user’s device. Network Doctor aims to organize those checks into a plain-English diagnosis, while acknowledging when the evidence does not establish a definite cause.
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- VERSATILE CABLE TESTING: Cable tester for data (RJ45) terminated cables and patch cords, ensuring comprehensive testing capabilities
- LARGE BACKLIT LCD: Backlit LCD display enables easy reading of pin-to-pin wiremap results, even in low-lit areas
- COMPREHENSIVE FAULT DETECTION: Test for Open, Short, Miswire, Split-Pair faults, Cross-over, and Shield, providing thorough fault detection
- INTUITIVE USER INTERFACE: User-friendly interface with three buttons and simple, easy-to-identify test responses, ensuring a smooth testing experience
- MULTIPLE TONE GENERATOR STYLES: Tone on a single wire, wire pair, or all 8 conductor wires using the multiple style tone generator (solid/warble); requires probe Cat. No. VDV500-123 (sold separately)
The project also describes interactive use, watch mode for intermittent failures, JSON output, saved diagnostic snapshots, remote and two-sided diagnosis, and drill-down tools. These capabilities make it useful both for a person investigating their own connection and for sharing structured information during troubleshooting. The project is licensed under Apache License 2.0. For current installation methods and versions, consult the project repository, since those details can change.
Why making the software useful is not the same as making it sustainable
Placzek’s stated tension is straightforward: he wants the software to remain useful without putting its useful features behind a paywall. In the DEV Community excerpt, he says, “I don’t want to turn the useful parts of Network Doctor into paid features just because I want the project to become sustainable.” The excerpt attributes the statement to Placzek, but the full article could not be verified here, so its surrounding context and publication year are not established.
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- Multifunctional NOYAFA NF-8508 Network Cable Tester: There are nine features to meet your needs. Continuity Testing, Cable Scan, Port Flash, Length Measurement, POE Power Supply Test, QC testing, Optical Power Meter, VFL and NVC function.It is perfectly suited for various engineering cabling projects, network troubleshooting, network equipment maintenance and testing scenarios. Its precise cable scanning and fault localization capabilities help you effortlessly pinpoint the root cause of issues.
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- High Efficiency Visual Fault Locator: Easy identification of fiber breakpoints, poor connections, bending or cracking. Excellent for finding the right fiber to splice or quickly finding a break. Emmiting Energy: standard wavelenth: 650nm. Fast flashing, slow flashing, high precison.The built-in self-calibration ensures stable long-term performance, and Class IIIa laser (output<5mW) ensures safe daily operation.
- PORT FLASHING:The indicator light on the connection port in the NF-8508 device flashes to help accurately locate the cable. Displays port information, including operating speed, duplex mode, and negotiation settings. Port lights flash on the same screen to show the port's operating speed, making it easy to pinpoint lines and ports.
- PoE Testing and Cable Length Test: PoE testing can check cable mapping polarity and voltage of PoE network switches, withstand 60VDC. Automatically detects and switches between 10M/100M/1000M modes, Includes cable tracking, short circuit test, interruption of circuit test and etc The RJ45 cable tester can quickly measure the length of the cable with a range of 200m. Not only network cables, but also phone lines and BNC cables.
That choice separates access to the tool from the question of who pays for ongoing work. Testing, packaging, releases, and maintenance take effort whether or not a project charges for access. A support model can invite users who value the software to contribute without making the core utility conditional on payment.
Two ways to support Network Doctor
The project’s official site presents two distinct routes. One helps fund continued project work; the other pays for a specific piece of troubleshooting assistance.
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- VERSATILE CABLE TESTING: Cable tester tests voice (RJ11/12), data (RJ45), and video (coax F-connector) terminated cables, providing clear results for comprehensive testing on unenergized Ethernet cables (not designed to test PoE)
- EXTENDED CABLE LENGTH MEASUREMENT: Measure cable length up to 2000 feet (610 m), allowing for precise cable length determination
- COMPREHENSIVE FAULT DETECTION: Test for Open, Short, Miswire, or Split-Pair faults, ensuring thorough fault detection and identification
- BACKLIT LCD DISPLAY: Backlit LCD screen displays cable length, wiremap, cable ID, and test results, ensuring easy readability in various lighting conditions
- EFFICIENT CABLE TRACING: Trace cables, wire pairs, and individual conductor wires using the multiple style tone generator (requires analog probe Cat. No. VDV500-123, sold separately), simplifying cable tracing tasks
| Option | What the payer receives | Price or terms |
|---|---|---|
| Voluntary sponsorship | Support for ongoing testing, packaging, releases, and maintenance. Sponsorship does not change access to the software or issue prioritization, according to the official Network Doctor site. | Optional; no price stated on the official site. |
| Personal Network Diagnosis | A review of one locally generated, sanitized support report, followed by a written explanation of the likely cause and specific troubleshooting steps. The offer includes one follow-up reply and does not guarantee a repair. | $25 USD, one time, for the first five cases, as listed by Network Doctor on October 4, 2026. The site estimates a usual response time of two business days after receiving enough information. |
What the paid diagnosis includes—and what it does not
The service is a narrowly scoped way to get help interpreting one problem, not a paid tier of the software. Network Doctor says the report is created on the user’s device with netdoc --support and that the project does not upload the file. Users should review and sanitize the report before sharing it, as the service itself calls for a sanitized report.
The deliverable is a written assessment of the likely cause and troubleshooting steps, plus one follow-up reply. It is diagnostic assistance, not a promise that the connection will be fixed. It also does not buy faster handling of project issues, feature requests, or development decisions. The $25 price, five-case cap, and response estimate are the offer shown on October 4, 2026, and may change.
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- The LAN cable tester can test both of the RJ11 telephone cable and RJ45 network cables such as RJ45 Cat5 Cat6 Cat7. Built-in high performance chip, which provide faster test results when checking wires and data points.
- The network provides the verification detail of wires to ensure that your networking is flowing optimally. And it will inform you whether the cables are paired and connected correctly or not.
- The network cable tester features a nice LED display which indicates. And the results that are easy for anyone to understand. It can be used by both professionals and unskilled home-users.
- Note: The cable tester needs a 9-volt battery to function. The battery is not included in the package at the time of purchase.
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How to choose between sponsorship and a diagnosis
- Choose sponsorship if the tool has helped you and you want to contribute to its ongoing maintenance without receiving a separate troubleshooting service.
- Choose Personal Network Diagnosis if you have one specific connection problem and want the developer to review a sanitized support report and provide written guidance under the offer’s stated terms.
- Choose neither if you do not need paid assistance or cannot share a suitably sanitized report. The tool remains available without sponsorship, and the site describes sponsorship as optional.
A small project in a broader open-source pattern
Sponsorship, enterprise support, and paid services are all models used by other open-source networking projects. OpenWISP and Sniffnet provide examples of those broader approaches, but the available material does not show a partnership or referral arrangement between either project and Network Doctor. Their models illustrate the range of ways developers may fund open-source work; they do not establish that one approach is right for every project.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What is known about the “first dollar” claim
The available DEV Community search excerpt says Network Doctor had made $0 when Placzek’s article appeared. Because the excerpt gives only “September 19” and no verifiable year, that should be read as a historical statement attributed to the author—not as a current revenue figure. The current official site documents ways to support the developer, but it does not establish how much the project has earned.
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- Multifunctional Network Cable Tester: TESMEN TLP-123A Supports RJ45 and RJ11, enabling rapid detection of line connectivity, short circuits, open circuits, miswiring, and cable shielding status. An essential tool for troubleshooting line faults and network maintenance, it effectively boosts your work efficiency
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