" But if the destination is not on the forbidden list, it's allowed to go through.

Outside Iran, the proxy servers are like transit points. Activists set up proxy servers on their own computers, using Internet Protocol numbers that don't appear on the forbidden list. Traffic from Iran can go through to those addresses with no problem. The data traffic is then forwarded to wherever it's destined to go, even if that destination is supposedly forbidden.

During the post-election crisis, proxy servers have been popping up like thousands of computerized "Casablanca" cafes around the world. The Pirate Bay, a popular file-sharing site based in Sweden, launched an anonymous Net-surfing forum to help Iran's opposition - but most of the proxy providers are amateurs."