A significant contributor to the development of the Internet, Postel was involved in early work on the ARPANET while at UCLA. He later moved to the Information Sciences Institute at the University of Southern California, where he spent the rest of his career. Postel served on the Internet Architecture Board and its predecessors for many years.
He was the Director of the names and number assignment clearinghouse, the Internet Assigned Numbers Authority (IANA), from its inception. Postel was the first member of the Internet Society and served on its Board of Trustees. He was the original and long-time .us Top-Level Domain administrator, and also managed the Los Nettos Network.
Perhaps his most famous legacy is from RFC 793, which includes a Robustness Principle often labeled Postel's Law: "be conservative in what you do, be liberal in what you accept from others" (often reworded as "be conservative in what you send, liberal in what you accept"). In digital circuits, this principle has long been an important aspect of what is known as the static discipline.
