ipv6-works check (three possible cases):
1. tagged: system-ipv6-works
2. tagged: system-ipv6-doesnt-work
3. untagged (none of the above tags is set)
I don't see the purpose of the untagged
status. Either IPv6 / IPv4 works, or not. What is the completely
untagged status supposed to tell me?
A "doesnt-work" tag is applied if the probe returns results for (in this case) some IPv6 measurements, and all of those results indicate a failure to reach the targets. If, on the other hand, the probe has a problem submitting results to the controller, then we don't know whether it can or cannot reach IPv6 targets, so it doesn't get either tag. In general you can consider a probe with a "connected" status, but none of (ipv4-works, ipv6-doesnt-work, ipv4-works, ipv6-doesnt-work), as having a problem submitting results due to some other issue.
The same applies to DNS checks. There's a tag for every case, plus
the "no-tag status":
DNS resolving check:
1. tagged: system-resolves-a-correctly
2. tagged: system-resolves-a-incorrectly
3. tagged: system-doesnt-resolve-a
4. untagged (none of the above tags is set)
Similar to above:
1. The DNS record returned is as expected
2. A DNS record is returned, but it is not the one expected
3. No DNS record could be returned
4. The relevant measurement results were not submitted