What each device is, how sure ScanWRX is, and why
Every identification carries a confidence label and the evidence behind it. A model number appears only when the device reported that model itself — everything else is capped below confirmed and labelled with what it was inferred from.
A scanner that always produces an answer is producing some answers it made up. That is tolerable when you are poking around your own network and unacceptable when you are putting the result in a document with your name on it.
Four grades, and what each one means
The device told us. An mDNS device-info record, an SNMP sysDescr, a model in its own web interface. This is the only grade a specific model number can reach.
Several independent signals agree — say, a Ubiquiti MAC prefix, an SSDP response naming UniFi, and the device answering as the default gateway.
One signal, usually a MAC manufacturer plus an open port that suits the category. Worth checking before you write it down.
It answered and said nothing about itself. Shown as its address, with no invented name and no invented category.
Every conclusion opens
Click a device and you get the list of what each probe returned and how much weight it carried. The identification is an argument you can check rather than an answer you have to take on faith — which matters when a client asks how you know.
The rule about model numbers
Internally the rule engine that matches signals to manufacturers and categories has no field for a model number. It is not that the code declines to fill it in; there is nowhere to put one. A model can only arrive from a device’s own report. That is a structural guarantee rather than a discipline, and it is the single most important design decision in the product.
Things that go wrong, and what we do about them
A Mac sharing a USB printer advertises the printer’s model over mDNS. Read naively, that turns a MacBook into a Brother HL-L2305. ScanWRX only trusts that field when the device also has a printing port open.
The MAC prefix 00:50:C2 belongs to the IEEE Registration Authority, which sub-delegates it. Reporting “IEEE Registration Authority” as the manufacturer is worse than reporting nothing, so ScanWRX reports nothing.
Some devices advertise an mDNS instance name that is not a name at all — one genuinely announced itself as 0,1,2. Names that carry no information are discarded rather than displayed.
What this does not do
- A device that reports nothing about itself gets no name. ScanWRX shows the address and says unknown rather than guessing from the MAC prefix alone.
- Randomised (locally administered) MAC addresses are never attributed to a manufacturer, because the address was not assigned by one.
- Inference is capped at 85% confidence no matter how many signals agree. Only a self-report reaches confirmed.
See it on your own network
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