On Fri, Jul 27, 2018 at 04:40:46PM -0700, Keifer Bly wrote:

Hello,

So today I w as checking my relay on tor metrics https://metrics.torproject.org/networksize.html

I noticed something strange, according to the graph, the number of bridges seems to have suddenly completely dropped to zero (the bridges line just after “2018-07”) and now slowly climbing back up. I am wondering did something happen that knocked all of the bridges offline? It seemed strange so I just thought I would report.

Yes, the Bridge Directory Authority changed, and Metrics only received the bridges from one of the new bridge dirauth. Unfortunately, nearly all of the existing bridges were still publishing to the old bridge dirauth. As a result, Metrics saw the number of bridges drop the approximately zero. Slowly bridges are updating and using the new bridge dirauth instead.

[0] https://blog.torproject.org/new-release-tor-0339-bridge-authority-update [1] https://lists.torproject.org/pipermail/tor-announce/2018-July/000162.html