Tor 0.2.8.1-alpha 发布，主要更新如下：
- Major features (security, Linux):
- When Tor starts as root on Linux and is told to switch user ID, it can now retain the capability to bind to low ports. By default, Tor will do this only when it’s switching user ID and some low ports have been configured. You can change this behavior with the new option KeepBindCapabilities. Closes ticket 8195.
- Major features (directory system):
- When bootstrapping multiple consensus downloads at a time, use the first one that starts downloading, and close the rest. This reduces failures when authorities or fallback directories are slow or down. Together with the code for feature 15775, this feature should reduces failures due to fallback churn. Implements ticket 4483. Patch by “teor”. Implements IPv4 portions of proposal 210 by “mikeperry” and “teor”.
- Include a trial list of default fallback directories, based on an opt-in survey of suitable relays. Doing this should make clients bootstrap more quickly and reliably, and reduce the load on the directory authorities. Closes ticket 15775. Patch by “teor”. Candidates identified using an OnionOO script by “weasel”, “teor”, “gsathya”, and “karsten”.
- Previously only relays that explicitly opened a directory port (DirPort) accepted directory requests from clients. Now all relays, with and without a DirPort, accept and serve tunneled directory requests that they receive through their ORPort. You can disable this behavior using the new DirCache option. Closes ticket 12538.