On Sat, Aug 24, 2019 at 12:46:52PM -0600, David Fifield wrote:
They looked at the default bridges in Tor Browser 8.0.3 (October 2018). Only 12 of 25 default obfs4 bridges were working. (I think most of the non-working bridges have since been pruned, e.g. in #29378, #30264.) The median bandwidth of the 12 working bridges was 368 KB/s, with a large variance: minimum of 67 KB/s and maximum of 1190 KB/s.
Yes, we've been cleaning up our default bridges over the last few months. Here's an up-to-date list of our current default bridges: https://trac.torproject.org/projects/tor/wiki/doc/TorBrowser/DefaultBridges
Besides the default bridges, they requested 135 bridges from BridgeDB, and found that only 70% (95/135) of them worked. (This has also been at least partially addressed by #30441.) BridgeDB bridges are faster than default bridges, with a median bandwidth of closer to 600 KB/s (Figure 1).
For context: many obfs4 bridges had an unreachable obfs4 port because some operators were not aware that they had to expose both their OR *and* their obfs4 port. Our documentation wasn't sufficiently clear about this. We have since reached out to all affected operators. Many responded and fixed the issue. We eventually had to blacklist the bridges of the operators who did not respond.
Cheers, Philipp