[tor-bugs] #30350 [Obfuscation/Snowflake]: Hello, in China, currently, Tor Browser 8.5a11 version can't connect to Tor network through Snowflake bridge.

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#30350: Hello, in China, currently, Tor Browser 8.5a11 version can't connect to Tor
network through Snowflake bridge.
-----------------------------------+--------------------------
 Reporter:  amiableclarity2011     |          Owner:  cohosh
     Type:  defect                 |         Status:  accepted
 Priority:  Immediate              |      Milestone:
Component:  Obfuscation/Snowflake  |        Version:
 Severity:  Normal                 |     Resolution:
 Keywords:                         |  Actual Points:
Parent ID:                         |         Points:
 Reviewer:                         |        Sponsor:
-----------------------------------+--------------------------

Comment (by cohosh):

 Reproduced the same error messages as above. Here is the snowflake log:
 {{{
  --- Starting Snowflake Client ---
 2019/05/01 [scrubbed] Rendezvous using Broker at: https://snowflake-
 broker.azureedge.net/
 2019/05/01 [scrubbed] Domain fronting using: ajax.aspnetcdn.com
 2019/05/01 [scrubbed] WebRTC: Collecting a new Snowflake. Currently at
 [0/3]
 2019/05/01 [scrubbed] snowflake-6DBRIeDzTRSQAX8e  connecting...
 2019/05/01 [scrubbed] Started SOCKS listener.
 2019/05/01 [scrubbed] SOCKS listening...
 2019/05/01 [scrubbed] WebRTC: PeerConnection created.
 2019/05/01 [scrubbed] WebRTC: OnNegotiationNeeded
 2019/05/01 [scrubbed] candidate:3179257411 1 udp 2122260223 [scrubbed]
 34616 typ host generation 0 ufrag aHT/ network-id 1 network-cost 50
 2019/05/01 [scrubbed] WebRTC: DataChannel created.
 2019/05/01 [scrubbed] candidate:4093403827 1 tcp 1518280447 [scrubbed]
 34327 typ host tcptype passive generation 0 ufrag aHT/ network-id 1
 network-cost 50
 2019/05/01 [scrubbed] SOCKS accepted:  {[scrubbed]   map[]}
 2019/05/01 [scrubbed] WebRTC: OnIceComplete
 2019/05/01 [scrubbed] Negotiating via BrokerChannel...
 Target URL:  snowflake-broker.azureedge.net
 Front URL:   ajax.aspnetcdn.com
 2019/05/01 [scrubbed] BrokerChannel Response:
 200 OK

 2019/05/01 [scrubbed] Received Answer.
 2019/05/01 [scrubbed] ---- Handler: snowflake assigned ----
 2019/05/01 [scrubbed] Buffered 179 bytes --> WebRTC
 2019/05/01 [scrubbed] Traffic Bytes (in|out): 0 | 179 -- (0 OnMessages, 1
 Sends)
 2019/05/01 [scrubbed] WebRTC: Collecting a new Snowflake. Currently at
 [1/3]
 2019/05/01 [scrubbed] snowflake-ZfQsJ6ktC81llUao  connecting...
 2019/05/01 [scrubbed] WebRTC: PeerConnection created.
 2019/05/01 [scrubbed] WebRTC: OnNegotiationNeeded
 2019/05/01 [scrubbed] WebRTC: DataChannel created.
 2019/05/01 [scrubbed] candidate:3179257411 1 udp 2122260223 [scrubbed]
 57118 typ host generation 0 ufrag nBCk network-id 1 network-cost 50
 2019/05/01 [scrubbed] candidate:4093403827 1 tcp 1518280447 [scrubbed]
 59751 typ host tcptype passive generation 0 ufrag nBCk network-id 1
 network-cost 50
 2019/05/01 [scrubbed] WebRTC: No messages received for 30 seconds --
 closing stale connection.
 2019/05/01 [scrubbed] WebRTC: closing PeerConnection
 2019/05/01 [scrubbed] WebRTC: DataChannel.OnClose [locally]
 2019/05/01 [scrubbed] WebRTC: Closing
 2019/05/01 [scrubbed] copy loop ended
 2019/05/01 [scrubbed] ---- Handler: closed ---
 2019/05/01 [scrubbed] SOCKS listening...
 }}}

 So the rendezvous was successful but the connection to the snowflake proxy
 is failing... I'm going to go with all of our snowflake proxies are being
 blocked.

 This brings to mind that not only do we need more snowflake proxies, we
 should probably keep track of where certain proxies have been blocked so
 we don't give these out to clients if there are non-blocked proxies they
 can use. Otherwise the user experience will be terrible.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30350#comment:3>
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