Little about Austin Heap’s first online venture, a site hosting free episodes of the cartoon “South Park,” suggested he would one day use his computer skills to challenge a government. But for the past few days, Heap, an IT director in San Francisco, has been on the virtual front lines of the crisis in Iran, helping people there protest the presidential election, which opponents of the incumbent regime maintain was fraudulent. Heap’s weapon in the past few days was the proxy server, a computer configured to act as an intermediary between a computer user and the Internet. Such servers have many legitimate functions, such as speeding response times, and some illegitimate ones, such as helping spammers hide their identities. What interested Heap was the use of a proxy server to bypass censorship. Properly configured, a proxy server could identify Web surfers in Iran and route them to Twitter and other sites the government had restricted. People around the world were posting network addresses for such proxies on Twitter and elsewhere, Heap said, but there was no organization and the servers were unpredictable.