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ooni / probe

OONI Probe network measurement tool for detecting internet censorship
https://ooni.org/install
BSD 3-Clause "New" or "Revised" License
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engine: add flag indicating if the probe network has ipv6 connectivity #2192

Open hellais opened 1 year ago

hellais commented 1 year ago

It's currently tricky to distinguish inside of tcp_connect measurements if an IPv6 target is unreachable due to it being blocked vs it being unreachable because the probe has no IPv6 connectivity.

I think we should add an initial check to the startup of a probe, when we do geoip lookup and resolver identification, that checks if there is IPv6 connectivity and if not present maybe even disable some measurements (it doesn't make sense to check if an IPv6 address is reachable if we have no working connectivity).

It looks like windows uses these endpoints to check for it: IPv4: http://www.msftconnecttest.com/connecttest.txt IPv6: http://ipv6.msftconnecttest.com/connecttest.txt

We could maybe do the same.

This is loosely related to captive portal detection too: https://github.com/ooni/probe/issues/1629

bassosimone commented 1 year ago

Good idea, I think we should definitely do that and the solution you propose seems great!