We estimate the number of users by analyzing the requests induced by clients to relays and bridges.
This graph shows the estimated number of clients connecting via bridges. These numbers are derived from directory requests counted on bridges. Bridges distinguish connecting clients by transport protocol, which may include pluggable transports, so that graphs are available for different transports. For further details check the documentation on Reproducible Metrics.
The following events have been manually collected in the metrics-timeline Git repository and might be related to the displayed graph.
|Dates||Places/Protocols||Description and Links|
Release of tor 0.3.5.14, 0.4.4.8, and 0.4.5.7. Changes the source of geolocation databases from Maxmind to IPFire.
blog post announcement ticket commit
Turkmenistan blocks the default obfs4 bridges PraxedisGuerrero and smallerRichard.
geoip and geoip6 databases updated to "IPFire Project Fri, 12 Mar 2021 05:05:24 GMT" (
|2021-03-11||Belarus Relays Unknown||
Drop of relay users in Belarus. Bridge users are not affected.
relay graph bridge graph
Fire in the OVHcloud data centers located in Strasbourg takes about 48 relays offline in AS16276.
OVHcloud advisory Twitter thread
Decommissioned flash proxy badge server, flashproxy.bamsoftware.com.
Decommissioned flash proxy facilitator: server, flashproxy-reg-email poller, and flashproxy-reg-appspot app.
Outage of the Snowflake bridge.
|2021-02-15 to 2021-04-27||Myanmar||
Nightly shutdowns of fixed-line Internet in Myanmar.
relay graph bridge graph OONI report IODA for start IODA for end Access Now post censorship-analysis issue
|2021-02-13||Belarus Bridges meek obfs4||
Blocking of default obfs4 bridges and email-distributed bridges in Belarus. Relay users are not affected.
ticket BBS thread NTC thread relay graph bridge graph
|2021-02-06 to 2021-02-07||Myanmar||
Internet shutdown in Myanmar.
relay graph bridge graph OONI report IODA
|2021-01-31 to 2021-02-01||Myanmar||
Partial Internet shutdown after coup in Myanmar.
relay graph bridge graph article IODA OONI report
Deployed version 0.5.3 of the Snowflake WebExtension, with improvements to NAT handling.
archive ticket comment
Release of Tor Browser 10.5a8, which fixes the bug preventing the use of default bridges.
blog post issue
Release of Tor Browser 10.5a7, which has a bug preventing the use of default bridges.
blog post issue issue
|2021-01-17 to 2021-01-21||snowflake Unknown||
Decrease in measured Snowflake users. May have been caused by a drop of NAT-unrestricted proxies.
mailing list thread comment
|2021-01-13 to 2021-01-17||Uganda||
Internet shutdown in Uganda during general election.
|2021-01-10 to 2021-02-03||onion||
Large amounts of traffic at directory authorities disrupts consensus, which causes v3 onion services to stop working because of a bug. Tor 0.3.5.13, 0.4.3.8, and 0.4.4.7 have a fix for the bug.
ticket blog post onion service traffic graph Tor blog post Tor Browser blog post status.torproject.org
Changed the DNS records for snowflake.freehaven.net and snowflake-broker.bamsoftware.com to be CNAME records for the corresponding torproject.net domains, rather than bamsoftware.com, in order to avoid malware warnings.
|2021-01-01 to present||China snowflake Unknown||
Increased failure to bootstrap using Snowflake from China.
|2020-12-17 to 2020-12-20||snowflake||
DDoS attack on Greenhost, where the Snowflake broker and bridge and onionperf instances are hosted.
2020-12-17 status 2020-12-20 status anti-censorship-team thread
|2020-12-05 to 2020-12-09||meek moat||
An update to an Azure CDN edge server TLS certificate causes an outage of meek and Moat. It is fixed by the release of Tor Browser 10.0.6, which updates the built-in public key pinning of obfs4proxy.
ticket blog post meek graph BridgeDB graph certificate transparency
|2020-11-08 to 2020-11-09||snowflake||
Outage of the snowflake bridge
|2020-10-27 to present||Tanzania, United Republic of <OR> obfs4||
Blocking of Tor and default obfs4 bridges during elections in Tanzania.
Sudden decrease of relay users in Belarus, from 4000 to 1000, with simultaneous increase of bridge users.
BBS thread NTC thread relay graph bridge graph
Deployed version 0.4.2 of the Snowflake WebExtension, with better counting of clients.
|2020-09-27 to 2020-11-10||Azerbaijan||
Blocking of social media and instant messaging in Azerbaijan during the 2020 Nagorno-Karabakh war
OONI/AIW report IPHR/AIW report relay graph bridge graph
Shutdown of default obfs4 bridge frosty.
Deployed version 0.4.1 of the Snowflake WebExtension, with NAT type detection in the browser.
|2020-08-09 to 2020-08-12||Belarus||
Internet shutdowns in Belarus, during protests following a presidential election.
Deployed NAT-aware matching at the Snowflake broker.
|2020-06-30 to 2020-07-23||Ethiopia||
Internet shutdown in Ethiopia. Restrictions were partially lifted 2020-07-15.
article article IODA relay users graph
Release of Tor Browser 10.0a1, the first release with Snowflake for Android.
blog post ticket
Release of Tor Browser 9.5a13, the first release with Turbo Tunnel session persistence features for Snowflake.
blog post ticket
Redeployed the Snowflake bridge with support for non–Turbo Tunnel clients and KCP–Turbo Tunnel clients, removing support for QUIC–Turbo Tunnel clients.
|2015-12-31 to 2020-06-04||Mexico||
The Telmex ISP in Mexico blocks seven directory authorities.
mailing list post article
This material is supported in part by the National Science Foundation under Grant No. CNS-0959138. Any opinions, finding, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. "Tor" and the "Onion Logo" are registered trademarks of The Tor Project, Inc.. Data on this site is freely available under a CC0 no copyright declaration: To the extent possible under law, the Tor Project has waived all copyright and related or neighboring rights in the data. Graphs are licensed under a Creative Commons Attribution 3.0 United States License.