[atlas] "funny" comment in pop-up display for a measurement? (v4/v6 addr mismatch)

Hi Philip

thanks for the feedback!

<blush>

This was a very complex way to find out that I'm having a DNS (v6) config
issue on my end.

Sorry for the noise!
Wilfried

Philip Homburg wrote:
> Hi Wilfried,
> 
> On 2014/01/15 18:44 , Wilfried Woeber wrote:
> 
>>Some more digging and some more confusion?
>>
>>Logged in, looking at "My measurements", selecting 1033944, a traceroutev6.
>>Bringing up the Map tab, clicking on the green balloon in Bremen (Probe ID
>>13255) with the *2* (hops) in it, pop-up comes up. Nice!
>>
>>But the *-comment at the bottom puzzles me, by saying:
>>
>>* The last address does not match the target IP (192.153.174.196)
>>
>>This is sort of obvious, as the address referred to is 2001:6f8:114e:4::1
>>What's the background for this behaviour?
> 
> 
> The target of your measurement, wsww2.cc.univie.ac.at, has, as far as I
> can tell, only an IPv4 address. So an IPv6 measurement should fail. And
> in fact most probes reported:
> 
> "result":[{"error":"name resolution failed: non-recoverable failure in
> name resolution"}]
> 
> One question that comes up is how you were able to run this measurement
> in the first place. Because the system usually doesn't allow running
> measurement towards targets that don't have an address for the selected
> address family.
> 
> This also why the UI complains about 192.153.174.196, because that is
> the IPv4 address of wsww2.cc.univie.ac.at.
> 
> There were 3 probes where name resolution resulted in an IPv6 address. 2
> of them have since changed their behavior and no longer resolve to an
> IPv6 address.
> 
> One probe, 13255, is rather curious, because it resolved
> wsww2.cc.univie.ac.at to 2001:6f8:114e:3::c099:aec4, which is
> interesting because c099:aec4 is exactly equal to the IPv4 address of
> wsww2.cc.univie.ac.at. So I suspect that this probe is behind a resolver
> that does DNS64.
> 
> Philip
> 
>