In summary, 3 of the pool of 12 STUN servers are inaccessible in Russia. One of them is blocked by censorship in Russia, and the other two look like geoblocking of Russian clients by the STUN service.
stun.voip.blackberry.com and the IP address 178.239.90.248 are on the unified register of blocked sites, the entry dated 2017-04-28
stun.stunprotocol.org is not on the unified register as far as I can tell, nor are its IP addresses 18.191.223.12 and 2600:1f16:8c5:101::108. … the domain resolves incorrectly only in Russia and Ukraine:
stun.altar.com.pl is not on the unified register, nor is its IP address
176.119.42.11. Its failures only start on 2022-03-09. Its domain usually resolves correctly, but in Russia the actual STUN phase usually results in a timeout.
By the way, in recent versions of Tor Browser this is easier to do. You can can do it just by entering a custom bridge address in the normal about:preferences#connection interface:
Today, @Shelikhoo merged a change to stop sending Hello Verify Request. This may overcome Snowflake blocking by DTLS fingerprint in some ISPs in Russia.
It is not present in any release yet, but you can test it manually. You need commit 10fd00068528fd6309bbb49f9dd0fea38f1ac5ef or later. The expected output is Bootstrapped 100% (done).
$ git clone https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
$ cd snowflake/client
$ go build
$ tor -f torrc
There may still be a problem with the standalone (non-browser) proxies, as the Hello Verify Request mitigation hasn’t been applied to them yet.
RE: It is not present in any release yet
I intend to release a new version and get the patch into Tor Browser in the immediate future.
RE: There may still be a problem with the standalone (non-browser) proxies
It would take some time to get all the standalone proxies to update(as evident in the case of distributed snowflake server support). But since the majority of the proxy are browser based, and snowflake client would retry automatically, it should connect eventually.
Sorry about that. The snowflake-client README is outdated in that regard. It’s still documenting an older, deprecated way to set configuration options. The example torrc file is a better representative. I opened an issue to update the README:
There are two ways to specify most settings: as a command-line argument in the ClientTransportPlugin line and as as a key=value parameter in the Bridge line. The key=value SOCKS parameters are the preferred form, but the command-line options still work. The command-line options will be global (not specific to a single Bridge line). If the same option is given on the command line and in a Bridge line, the Bridge line setting wins.
So yes, you can move one or more settings out of the Bridge line and into the ClientTransportPlugin line. For example, you can change