The probe counted any well-formed packet from the server as "the server
answers", checking only the transaction id and a minimum length. REFUSED
and SERVFAIL are well-formed packets. So a server actively refusing this
client would have been reported as healthy, and the finding — whose whole
output is "the network is fine, your device is not" — would have pointed
confidently at the wrong component.
It now requires rcode 0 and at least one record, and reports a refusal as
what it is: a working server saying no, which points back at the network.
The rcode is named rather than numbered, because "REFUSED" is a fact an
operator can act on and "rcode 5" is a lookup.
Caught by decoding what fmr's router actually replied — ab cd 81 80 00 01
00 02, NOERROR with two answers — after realising the earlier check only
counted bytes. The reply was genuinely good, so the finding on the tablet
stands; the check was wrong regardless.
The advice is broader too. That tablet's fault survived a reboot, which
makes "toggle wifi and it clears" wrong as a flat claim: it now says what
to look at when a restart does not fix it — something on the device
filtering DNS, or a per-client rule on the router.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
