Subject: Feedback from China [April 2025]: Increased GFW Censorship; obfs4/meek/snowflake unusable, webtunnel connects but is quickly blocked
Hello Tor Community and Developers,
I am writing to report on the current situation regarding Tor bridge accessibility from mainland China, particularly in light of what appears to be recently intensified GFW censorship, potentially related to cross-strait tensions.
My observations over the recent period are as follows:
Obfs4 Bridges: Seem to be completely blocked. I am consistently unable to establish connections using obfs4.
Meek-azure Bridges: Similar to obfs4, meek-azure appears to be entirely unusable from my location. Connections fail.
Snowflake Bridges: Snowflake also seems ineffective currently. Establishing a connection has not been successful.
Webtunnel Bridges: This is the most noteworthy observation. Unlike the others, webtunnel bridges can initially establish a connection to the Tor network. However, these connections are extremely unstable and short-lived. They typically get blocked after a very short duration, sometimes just minutes, other times maybe up to a few hours. After being blocked, reconnecting to the same bridge (or even different webtunnel bridges) often fails for a while.
Summary:
While obfs4, meek-azure, and snowflake are effectively non-functional for me right now, webtunnel shows a glimmer of hope by being able to connect, even if only temporarily. This suggests the GFW is actively detecting and blocking webtunnel traffic, but perhaps with less efficiency or speed compared to the methods used against other pluggable transports.
I wanted to share this feedback directly, hoping it might be valuable for the development team. The fact that webtunnel can still punch through the firewall initially, even briefly, might offer insights for improving its resilience or developing new circumvention techniques. Any advancements in this area would be incredibly helpful for users in highly censored regions like China.
Thank you for your tireless work on Tor.