如果 Tor 访问被阻止该怎么办？
Direct access to the Tor network may sometimes be blocked by your Internet Service Provider or by a government. Tor Browser includes some circumvention tools for getting around these blocks. These tools are called "pluggable transports".
可插拔传输类型
目前提供四种可插拔传输，更多工具正在开发中。
| 可插拔传输 | 描述 |
|---|---|
| obfs4 | obfs4 makes Tor traffic look random, and also prevents censors from finding bridges by Internet scanning. obfs4 bridges are less likely to be blocked than its predecessors, obfs3 bridges. |
| meek | meek transports make it look like you are browsing a major web site instead of using Tor. meek makes it look like you are using a web site from a CDN or cloud provider. |
| Snowflake | Snowflake routes your connection through volunteer-operated proxies to make it look like you're placing a video call instead of using Tor. |
| WebTunnel | WebTunnel masks your Tor connection, making it appear as if you're accessing a website via HTTPS. |
使用可插拔传输
In Tor Browser, Lyrebird is the name of Tor's program that implements several pluggable transport protocols, including obfs4, meek, Snowflake, and WebTunnel. It also implements the ability to request bridges and supports Connection Assist.
To use a pluggable transport, click "Configure Connection" when starting Tor Browser for the first time. Under the "Bridges" section, locate the option "Choose from one of Tor Browser's built-in bridges" and click on "Select a Built-In Bridge" option. From the menu, select whichever pluggable transport you'd like to use.
选择可插拔传输，然后点击“连接”保存设置。
或者，当 Tor 浏览器正在运行时，可在汉堡菜单 (≡) 下选择“设置”，然后在边栏点击“连接”。 在“网桥”部分，找到选项“选择 Tor 浏览器内置网桥”，然后点击“选择内置网桥”。 从菜单中选择任一可插拔传输，然后点击“确定”。 关闭选项卡，您的设置将自动保存。
配置内置网桥
什么是网桥？
Most pluggable transports, such as obfs4, rely on the use of "bridge" relays. 如同普通 Tor 中继，网桥由志愿者运行；不过，与普通中继不同的是，网桥并未公开列出，因此不会被封锁者轻易识别。 Bridges help you securely access the Tor network in places where Tor is blocked.
Using bridges in combination with pluggable transports helps circumvent blocks against Tor, but may slow down the connection compared to using ordinary Tor relays.
其他可插拔传输，如 meek 和 Snowflake，使用了不同的反审查技术，并不依赖于网桥。使用此类传输工具，用户无需获取网桥地址。
我该使用哪种可插拔传输？
Tor 网桥菜单所列的可插拔传输工具，都使用不同的方式运行，其有效性取决于个人所处的环境。
If you are trying to circumvent a blocked connection for the first time, you should try the different transports: obfs4, webtunnel, snowflake, or meek-azure.
如果尝试所有选项都无法成功连网，那么需要请求网桥或者手动输入网桥地址。
Read the Getting bridges section to learn how to obtain them.