Blocking has been an issue for the international company I work for. The company recently switched 4000+ users to Gmail and Google Apps only to find after the f

Blocking has been an issue for the international company I work for. The company recently switched 4000+ users to Gmail and Google Apps only to find after the facts that nearly 20% of the workforce would have little or no access to most of the Google Apps sites as they are in China (I guess a bit more testing should have been in order...). I hacked a solution, involving stunnel for encrypted communications, ss5 (a SOCKS5 proxy server), Proxy Auto-Config files (PAC) files and the Web Proxy Auto-Discovery protocol (WPAD)... An installer is used to easily deploy the whole thing and configure the system. PAC files are used by the browser to redirect traffic based on URL pattern matching. Instead of going through the local Internet, requests that match the rules for known bocked sites are diverted to a local stunnel service running on the user's machine (or a local server depending on the configuration). The encrypted requests are then sent to a server in Hong Kong running the SOCKS5 proxy (we actually now use multiple servers on different HK ISPs and do some load balancing for better results). From the point of view of the user, the system is transparent: it just works, they have nothing to do once their machine is configured. I tried many setups, but the various measures used in China to disrupt traffic required the data stream to be encrypted for reliable results. The only issue we face is due to the really unpredictable quality of the network in China: most ISPs have limited international bandwidth and depending on the ISP, the time of day, etc there can be large variations in quality. I need to write about this one day...