Why don't my proxies work anymore?

September 23, 2009 5:08 PM

Why have my proxies (Privoxy and GAppProxy) suddenly quit working? I'm using an up-to-date Vista installation.

I use proxies periodically to get past China's Great Firewall. In the past, a strategy of Tor (by means of Vidalia/Privoxy/Torbutton) and GAppProxy (through FoxyProxy, set up using these instructions). I never use the two at the same time, i.e. if I'm using Tor, I'm not using GAppProxy, and vice versa. When I was last in China, in July, I had been using this setup for a few months with no problems.

I've just returned to China, and after a day or two of flawless operation, both proxies have quit working. To clarify, both proxy setups manage to get past the Great Firewall and transfer data. However, within a few seconds of data transfer through the proxy, I get a message from windows stating, "Privoxy has stopped working" or "HTTP Proxy. 127.0.0.1:8000 has stopped working" in the case of GAppProxy. Privoxy is running on port 8118.

Restarting the computer or the proxies doesn't solve the problem. Running one without the other doesn't solve the problem. Is there a possibility that something other than my computer is causing the problem, perhaps new strategies used by the Great Firewall spike the proxy somehow? The proxies remain operational if they are not in use, which is to say, if I start Privoxy or GAppProxy and don't transfer data through them, the services run with no problem.

While I haven't installed any internet-using programs in the week I've been back in China, since I didn't use the proxies for two months while outside of China, I can't be sure that the problem is a result of new conditions.

How can I troubleshoot this problem?

posted by msbrauer to computers & internet (3 comments total)

I've read they've been stepping up counter-measures specifically aimed at closing down a lot of the more popular methods to get round the GFW - OpenVPN is very patchy at the minute for me. Still getting some joy from the Firefox add-on Gladder which should be a quick fix and some of the proxies that allow HTTPS such as sneakme dot net work in that mode even though now blocked in plain HTTP.
Not much by the way of actual technical advice to offer though, I'm afraid.
posted by Abiezer at 5:25 PM on September 23

Wild stab, but have there been any changes to your local antivirus since you last used it? This sounds like an over-aggressive AV or HIDS killing down a suspicious process.
posted by These Premises Are Alarmed at 5:32 PM on September 23

Hmm..hadn't thought about the antivirus. Haven't made any changes to it, beyond the daily or so updates to the virus database. Using Avast. Tried disabling it, and the problem persists.
posted by msbrauer at 6:38 PM on September 23