Though he wielded immense power in helping to set technical standards, particularly in the area of domain names, he worked behind the scenes, shunning publicity, and never made a fortune from his pioneering position.

"Jon could have been a millionaire. It just wasn't his bag," said Professor Dave Farber, who teaches telecommunications at the University of Pennsylvania and had been Postel's thesis adviser.

He was not elected to the position of responsibility he held in the Internet community - he was simply, in the words of the White House's Internet policy adviser, Ira Magaziner, "the guy they trust".

'Most powerful person on the Net'

"He really was the most powerful person on the Net," Professor Farber said.

"He came by that power legitimately, as the only person who could command the respect and loyalty of the whole community."

The Economist magazine said, simply, "if the Net does have a God, he is probably Jon Postel."

He began working on what became the Internet in 1969 as a 25-year-old graduate student at UCLA. He went on to edit the Requests for Comment which become the Internet's technical standards.

It was not until late in his life that the extent of his influence was understood outside the technology community, and his power was questioned by commercial interests.

Domain name dispute

In 1997 he touched off a debate over how names for Web sites and other internet resources are distributed.

At present, if you want to create a Web site in the .com, .net or .org 'domains' - http://www.bbcnews.org, for example - you have to register the name with an American company, Network Solutions, and pay a fee.

As the number of organizations going online has grown, disputes have arisen over ownership of those names, and Network Solutions' monopoly has been attacked.

Mr Postel suggested an alternative, and his plan inevitably came under fire from competitors.

"It's not appropriate for a single individual like Dr Postel to make those policy decisions," a Network Solutions executive said earlier this year.

Among his responsibilities was assigning all the numbers that go with Internet names, through the Internet Assigned Numbers Authority which he formed and heads.

Postel takes control

In early 1997, as the US government was discussing domain name alternatives, he used this power to transfer control temporarily away from Network Solutions to his own server.

No disruption was caused to the running of the Internet and he said he was merely testing the technical feasibility of any future hand-over of power, but critics accused him of sabre-rattling.

"I'm not on any power trip," he said.

He always maintained that he was motivated solely by the public good and that decisions on domain naming "have to be made fairly and with the long-term benefit of the Internet community in mind".

This philosophy and his contributions will play a critical role in shaping the future of the Internet, for years to come.

Casual style

His style was famously casual - in the early 1970s, he was sent to help the US Air Force with its computers and was ordered to wear shoes before he entered their plane.

Among his other interests were hiking, backpacking and reading British detective stories.

A modest man, when told people might be interested in what kind of person he was, he once told an interviewer, "If we tell them, they won't be interested any more."

He is survived by a brother, Mort Postel and a partner, Susan Gould.