How Iranians Get Around Web Censors

Iranians protesting the outcome of their country's presidential election, and stymied by Internet censorship, have a secret weapon — proxy servers.

Following the controversial announcement that President Mahmoud Ahmadinejad had won in a landslide late Friday, Iranian authorities disabled cell-phone text-messaging and blocked Web sites such as Facebook and YouTube.

But Iranians who'd voted for the "loser," Mir Hossein Moussavi, quickly discovered what Chinese Web users have long known: certain Internet-linked servers can serve as relays, allowing access to blocked sites.

Instead of two machines communicating directly — as usually happens when a Web user goes to a Web site — the proxy server acts as a "man in the middle," bouncing data from one to the other and back again.

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In that way, an Iranian or Chinese user can reach blocked domains or IP addresses. If one proxy server is blocked, others can quickly spring up, resulting in a game of whack-a-mole with the authorities.

"Reportedly good Inet proxies out of Iran:,,, and," was one messaged that bounced around Twitter Monday morning.

Those numbers indicate the IP address and port number of proxy servers that Iranians could use to upload videos of protests to YouTube.

From the two dozen clips posted at one leading dissident "channel,", a lot was getting through.

Twitter was still up in Iran over the weekend, a possible accidental omission on the part of Tehran's censors, as was the photo-sharing site Flickr.

That allowed dozens of tech-savvy, English-speaking dissidents to communicate with the outside world, and each other — and show everyone what was going on in the streets of Tehran.