In Memory of Jon Postel

By: Wendy Rickard

Date: February 7, 2009

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Jon Postel
Jon Postel. Photo by Peter Löthberg

Last October marked the 10-year anniversary of the passing of Internet engineer, standard-bearer, and icon Jon Postel. While Jon’s work contributed in countless ways to the advancement and smooth functioning of the Internet, it was his role as RFC editor-a role he created and held from April 7, 1969, until his untimely death on October 16, 1998-and his work with the IANA (Internet Assigned Numbers Authority) that are of particular significance to the IETF community.

To those who knew him, Jon was a brilliant and astute engineer whose soft-spoken manner belied his dogged pursuit of excellence, a characteristic especially evident in his role as editor of the RFC document series. His feedback to authors was not confined to grammar and phrasing, for which he was a stickler; it included any potential inconsistencies, ambiguities, and duplications of effort. Jon’s longtime colleague Joyce Reynolds, wrote in RFC 2555 that while operating systems and computers have changed over the years, “Jon’s perseverance about the consistency of the RFC style and the quality of the documents remained true.”

Equally impressive, especially in hindsight, was Jon’s ability to anticipate the need for keeping track of the work. “Somehow, Jon knew, even 30 years ago, that it might be important to document what was done and why, to say nothing of trying to capture the debate for the benefit of future networkers wondering how we’d reached some of the conclusions we did (and probably shake their heads…),” wrote Vint Cerf, also in RFC 2555.

It wasn’t always easy. According to Jake Feinler, “Jon often took merciless flak from those who wanted to continue discussing and implementing, or those whose ideas were left on the cutting-room floor. Somehow he always managed to get past these controversies with style and grace and move on.”

Jon not only edited the RFC series; he also authored or coauthored more than 200 of them (see In September 1981, he wrote RFC 791, which described the Internet Protocol, as well as RFC 792 (the Internet Control Message Protocol) and RFC 793 (Transmission Control Protocol). In 1982, he authored RFC 821, which defined the Simple Mail Transfer Protocol.

According to Bob Braden, who worked with Jon at the Information Sciences Institute of the University of Southern California, there were many aspects of the IETF culture that matched Jon very well. “Dedication to making things that work, a neverending attempt to keep protocols as simple and powerful as possible, and a slight counter-cultural tinge all characterized Jon,” Bob wrote in a memo to the IETF after learning of Jon’s passing. Jon’s prescience, talent, and meticulous approach to his work are characteristics that stand out for many engineers and Internet developers from that time. “As far as I know,” wrote Bob, “Jon had no model to follow when he wrote RFCs 791, 792, and 793, yet the result was a model that I personally have spent nearly 20 years studying and trying to emulate. Jon’s contribution was not just the skill and grace of his editorial style; in writing these documents, Jon determined much of the detailed content, interpreting and elaborating the ideas of others to produce one seamless whole.”

In January 1980, Jon wrote the statement that many say most accurately described his philosophy toward life: “In general, an implementation should be conservative in its sending behaviour, and liberal in its receiving behaviour.” The comment, which appeared in RFC 760, was amended a year later by Jon in RFC 793 to the oft-repeated: “Be conservative in what you do; be liberal in what you accept from others.”

On the 10-year anniversary of his passing, Vint, who wrote Jon’s obituary and published it under the playful title of RFC 2468 (I Remember IANA), reminds us of the significance of that statement, not just for Jon, but also for the community at large. “[Although] he meant [it] in the context of detailed protocols, it also serves as a reminder that in a multistakeholder world, accommodation and understanding can go a long way towards reaching consensus or, failing that, at least toleration of choices that might not be at the top of everyone’s list.”

Vint has served as a prolific interpreter of Jon’s legacy, describing him as the network’s Boswell.(1)However, it was Jon’s “devotion to quality and his remarkable mix of technical and editing skills that permeate many of the more monumental RFCs that dealt with what we now consider the TCP/IP standards,” wrote Vint. “Many bad design decisions were reworked thanks to Jon’s stubborn determination that we all get it “˜right.’ As the editor, he simply would not let something go out that didn’t meet his personal quality filter. There were times when we moaned and complained, hollered and harangued, but in the end, most of the time, Jon was right and we knew it.”



1. James Boswell was an 18th Century Scottish lawyer, diarist, and author whose name has become a term used to describe a constant companion and observer. Read more…

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