Vint Cerf

Who Vint Cerf is

Vinton G. Cerf, known as Vint, is an American computer scientist who designed the internet‘s core protocols with Robert Kahn. A protocol is an agreed set of rules for how computers exchange data. Their Transmission Control Protocol and Internet Protocol, usually written together as TCP/IP, remain a mainstay of the internet’s technical foundation, according to DARPA, the U.S. defense research agency that funded the work.¹

The Association for Computing Machinery (ACM) gives his birth as June 23, 1943, in New Haven, Connecticut, and the Japan Prize Foundation lists the same date.²³ He earned a bachelor’s degree in mathematics at Stanford University in 1965. He then worked as a systems engineer at IBM from 1965 to 1967, supporting a programming language called QUIKTRAN, before taking a master’s degree in 1970 and a doctorate in 1972 in computer science at the University of California, Los Angeles (UCLA).²⁴

His career runs through many of the bodies that built and later ran the network: Stanford, DARPA, MCI, the Corporation for National Research Initiatives (CNRI), the Internet Society, ICANN and Google.² The White House’s 2005 biography calls him a “Father of the Internet,” and the Japan Prize Foundation gives the same title to Cerf and Kahn together.⁵⁶

The internet and the World Wide Web are not the same thing. In a 2005 question-and-answer session, Cerf and Kahn credited Tim Berners-Lee with creating the web, and described their own work as the architecture and protocols for joining different kinds of networks.⁷ The web is one service that runs over their protocols.

UCLA and the ARPANET, 1968 to 1972

ARPANET was the first network funded by ARPA (now DARPA). At UCLA, Cerf was the principal programmer at the Network Measurement Center, an ARPA-funded lab run by Leonard Kleinrock. He wrote host software that sent traffic into the ARPANET, measured the results and tried to overload the network to find its limits.⁸

He also took part in the Network Working Group, led by Steve Crocker, which worked out the host-to-host protocols and higher-level ones such as Telnet for remote login, FTP for file transfer and email.⁸ On October 16, 1969, Cerf wrote RFC 20, “ASCII format for Network Interchange.” An RFC (Request for Comments) is a numbered document in the series where internet standards are published. RFC 20 set out how the network would use ASCII, the code that assigns numbers to letters and symbols, and it is still an Internet Standard, numbered STD 80.⁹

Cerf has described the October 29, 1969, link between UCLA and the Stanford Research Institute (SRI) as the first connection between two computers on the network.¹⁰ Around 1969 to 1970, Kahn came to UCLA to test the network and expose weaknesses that could lock it up. Cerf recalled that this was when the two first met.⁸

In 1972 Cerf returned to Stanford as an assistant professor, a post he held until 1976, teaching in the computer science and electrical engineering departments.²⁴

Designing TCP/IP with Bob Kahn, 1973 to 1974

Kahn joined ARPA’s Information Processing Techniques Office as a program manager in 1972.¹ His starting idea, which the Internet Society’s history calls open-architecture networking, was that separately designed networks could still be joined by a common set of rules.¹¹ ARPA’s packet communications program by then also covered networks that sent packets over radio and by satellite, alongside the ARPANET.⁸

In the spring of 1973 Kahn visited Cerf at Stanford, and the two began working on how to connect those three kinds of network. Cerf later said: “That became known, at least to Bob and me, as the Internet problem.”⁸ In June 1973 they invited networking researchers from several countries to a seminar on the design.²

The first written version, a working paper numbered INWG 39, was handed out at a meeting at the University of Sussex in England in September 1973.¹¹⁸

In May 1974 the journal IEEE Transactions on Communications published their paper, “A Protocol for Packet Network Intercommunication.” Cerf signed it from Stanford’s Department of Computer Science and Electrical Engineering, and Kahn from ARPA.¹² The paper’s main ideas were:

• A shared host protocol. A transmission control program, TCP, running on each computer, handled packets of different sizes, failed transmissions, sequencing, flow control, end-to-end error checking, and setting up and closing logical connections between programs.¹²
• Gateways between networks. The paper named the machine joining two networks a GATEWAY. Gateways passed traffic from one network to the next and could break packets into smaller pieces for networks that needed them.¹² Today these machines are called routers.²
• Addresses for many networks. The proposed address had 8 bits for the network and 16 bits for the host’s TCP, enough for 256 networks.¹²

The paper thanks researchers including Robert Metcalfe, Donald Davies, Louis Pouzin and Steve Crocker.¹² A detailed specification followed in December 1974 as RFC 675, “Specification of Internet Transmission Control Program,” by Cerf, Yogen Dalal and Carl Sunshine of the Stanford group.¹³⁸

The first TCP did two jobs: moving packets between networks and managing the conversation between two computers. The design was later reorganized into two protocols. IP took over addressing and forwarding of individual packets, and TCP kept flow control and recovery from lost packets.¹¹ Cerf recalled that IP was split out in the final iterations of the design.⁸ Cerf and Kahn did not patent the technology.⁴

The lasting definitions were published in September 1981. RFC 791, edited by Jon Postel at the University of Southern California’s Information Sciences Institute for DARPA, defines IP with addresses fixed at 32 bits, and says it draws on six earlier editions of the specification.¹⁴ TCP’s 1981 standard, RFC 793, also by Postel, was replaced in August 2022 by RFC 9293, which brings the changes made to TCP over decades of use together into one specification.¹⁵

DARPA and the 1983 switch to TCP/IP

From 1976 to 1982 Cerf was a program manager in DARPA’s Information Processing Techniques Office.² On November 22, 1977, a demonstration sent data across three different networks, the Packet Radio network, the Packet Satellite network and the ARPANET.¹⁰

The ARPANET itself still ran an older host protocol, the Network Control Protocol, or NCP. In November 1981 Postel published RFC 801, a plan to move every ARPANET host to TCP/IP. Each host was to begin its TCP/IP work by January 1, 1982, and on January 1, 1983, NCP would be removed from service and every service would run over TCP.¹⁶

Cerf recalled that ARPA pushed sites along in 1982 by briefly cutting off traffic that was not TCP/IP, first for one day and later for two days.⁸ He left DARPA for MCI around October 1982, before the deadline.⁸ The ACM credits Kahn with helping guide ARPANET sites through the 1983 change.²

The switch happened on January 1, 1983. The Internet Society’s history describes it as a flag-day transition, in which all hosts had to convert at the same time.¹¹ Cerf remembered protests, some exceptions, and most hosts converted or off the network by about June.⁸ He has written that January 1, 1983, was the day the internet was “operationally born.”¹⁰

MCI Mail, CNRI and the Internet Society

At MCI, Cerf was vice president of Digital Information Services from 1982 to 1986.² He joined to build MCI Mail, based on an idea of Robert Harcharik’s for a “digital post office.”⁸ The service launched on September 27, 1983. Cerf recalled that it could send and receive telex messages and reach postal addresses through a print interface, and that fax was added later.⁸⁴

In 1986 he joined Kahn as a vice president of the newly formed CNRI, where he stayed until 1994.² His work there covered digital libraries, knowledge robots and gigabit networking.⁴ In 1989 he arranged for MCI Mail to become the first commercial email service to use the internet; Google’s biography of him says he did this with Kahn.²⁴

Cerf and Kahn also started the Internet Society (ISOC), which was formed under CNRI with Cerf in a leading role.²¹¹ Sources give different founding dates:

• The Internet Society’s oral history of its founding says Cerf announced it in June 1991 at the INET ’91 conference in Copenhagen. Operations began on January 1, 1992, as an activity of CNRI, and the society was formally incorporated in early December 1992.¹⁷
• The Internet Society’s Brief History of the Internet dates its formation to 1991, and the ACM says Cerf and Kahn founded it that year.¹¹²

Cerf was the society’s first president, from 1992 to 1995, and chaired its board in 1999.¹⁷¹⁸ In 1994 he went back to MCI as a senior vice president, a role he held until 2005, to help the company enter the internet business.²⁴

ICANN, Google and later work

The Internet Corporation for Assigned Names and Numbers (ICANN) coordinates the internet’s naming system and the supply of IP addresses, and runs the accreditation system for domain registrars.¹⁹ Cerf joined its board in November 1999 and became chairman in November 2000. He concluded his board term at ICANN’s Los Angeles meeting in November 2007, after eight years of service.²⁰

Cerf joined Google in October 2005 as vice president and Chief Internet Evangelist, working on internet policy and standards.¹⁸ On June 30, 2026, TechCrunch reported that Cerf, then 83, would step down from the role the following week, and that a Google spokesperson had confirmed he would be stepping down.²¹

Other roles have kept him close to the network’s future:

• IPv6. Since July 1999 he has been honorary chairman of the IPv6 Forum, which promotes the newer version of the Internet Protocol.¹⁸
• The interplanetary internet. He has been a distinguished visiting scientist at NASA’s Jet Propulsion Laboratory since 1998, and has worked with NASA since the mid-1990s on a network for the solar system.¹⁸⁴ In 2005 he called the project “as close as you can come to living a science fiction story.”⁷
• The ACM. He served as president of the ACM, the computing society, from 2012 to 2014.²

Awards and honors

Most of Cerf’s major awards were shared with Kahn. The table lists the ones confirmed by the awarding body or a government record.

The ACM’s announcement cited the pair’s pioneering work in designing and implementing the internet’s basic communications protocols.²² The IEEE’s Medal of Honor citation reads, in part, “for co-creating the Internet architecture and providing sustained leadership in its phenomenal growth.”²⁵ At the 2005 ceremony, President George W. Bush said that by developing a common digital language for computers across networks, the two men had prepared the way for a technological revolution.²³

The ACM’s list adds the International Telecommunication Union’s Silver Medal (1995), the IEEE Alexander Graham Bell Medal (1997), the Marconi Award (1998) and the Harold Pender Award (2010). It also lists him as a fellow of the IEEE, the ACM, the American Academy of Arts and Sciences, the American Association for the Advancement of Science, the British Computer Society and the National Academy of Engineering.²

Timeline

1. June 30, 2026Google confirms Cerf will step down as its Chief Internet Evangelist²¹
2. January 31, 2023IEEE names Cerf the 2023 Medal of Honor recipient²⁵
3. 2013Cerf shares the 2013 Queen Elizabeth Prize for Engineering²⁴
4. 2008Cerf and Kahn receive the Japan Prize⁶
5. November 2007Cerf concludes his term as ICANN board chairman²⁰
6. November 9, 2005Cerf and Kahn receive the Presidential Medal of Freedom²³
7. October 2005Cerf joins Google as vice president and Chief Internet Evangelist¹⁸
8. February 16, 2005ACM names Cerf and Kahn winners of the 2004 Turing Award²²
9. November 2000Cerf becomes chairman of the ICANN board²⁰
10. June 1991Cerf announces the Internet Society at INET '91 in Copenhagen¹⁷
11. 1989MCI Mail becomes the first commercial email service to use the internet²
12. September 27, 1983MCI Mail, built under Cerf, launches⁸
13. January 1, 1983ARPANET switches from NCP to TCP/IP¹⁶
14. May 1974Cerf and Kahn publish "A Protocol for Packet Network Intercommunication"¹²
15. October 16, 1969Cerf writes RFC 20, ASCII format for Network Interchange⁹

What it means for your website

See also

• Internet
• IP address
• HTTP
• ICANN
• Jon Postel
• Tim Berners-Lee
• How does a website work
• Domain registrar

References

1. TCP/IP. Defense Advanced Research Projects Agency (DARPA). accessed October 22, 2026.
2. Vinton Cerf, A.M. Turing Award laureate. Association for Computing Machinery. accessed October 22, 2026.
3. Laureates of the Japan Prize: Dr. Vinton G. Cerf. The Japan Prize Foundation. accessed October 22, 2026.
4. Vint Cerf: technical biography. Google. accessed October 22, 2026.
5. Dr. Vinton Cerf and Dr. Robert Kahn. The White House (archived), George W. Bush administration. 2005. accessed October 22, 2026.
6. 2008 Japan Prize Laureates: Information Communication Theory and Technology. The Japan Prize Foundation. 2008. accessed October 22, 2026.
7. Ask the White House: Dr. Vinton Cerf and Dr. Robert Kahn. The White House (archived), George W. Bush administration. 2005-11-09. accessed October 22, 2026.
8. Oral-History: Vinton Cerf (interviewed by David Hochfelder, IEEE History Center). Engineering and Technology History Wiki. 1999-05-17. accessed October 22, 2026.
9. RFC 20: ASCII format for Network Interchange. V. Cerf, UCLA, RFC Editor. 1969-10. accessed October 22, 2026.
10. Vint Cerf's top moments from 50 years of the Internet. Vint Cerf, Google Blog. 2019-10-29. accessed October 22, 2026.
11. A Brief History of the Internet (Leiner, Cerf, Clark, Kahn, Kleinrock, Lynch, Postel, Roberts, Wolff). Internet Society. accessed October 22, 2026.
12. A Protocol for Packet Network Intercommunication (Vinton G. Cerf and Robert E. Kahn), IEEE Transactions on Communications, vol. COM-22, no. 5, pp. 637-648. IEEE, copy hosted by Boston University. 1974-05. accessed October 22, 2026.
13. RFC 675: Specification of Internet Transmission Control Program. Vinton Cerf, Yogen Dalal and Carl Sunshine, RFC Editor. 1974-12. accessed October 22, 2026.
14. RFC 791: Internet Protocol. Jon Postel (ed.), Information Sciences Institute, for DARPA, RFC Editor. 1981-09. accessed October 22, 2026.
15. RFC 9293: Transmission Control Protocol (TCP). W. Eddy (ed.), Internet Engineering Task Force, RFC Editor. 2022-08. accessed October 22, 2026.
16. RFC 801: NCP/TCP Transition Plan. Jon Postel, Information Sciences Institute, RFC Editor. 1981-11. accessed October 22, 2026.
17. An Oral History of the Internet Society's Founding. Internet Society. accessed October 22, 2026.
18. Vint Cerf. Internet Hall of Fame. accessed October 22, 2026.
19. What Does ICANN Do?. ICANN. accessed October 22, 2026.
20. ICANN Invites Internet Community to Pay Tribute to Dr. Vint Cerf. ICANN. 2007-11-02. accessed October 22, 2026.
21. The 'Father of the Internet' is finally retiring. Tim Fernholz, TechCrunch. 2026-06-30. accessed October 22, 2026.
22. ICANN Chairman of the Board Wins Prestigious Turing Award. ICANN (reproducing the ACM announcement). 2005-02-16. accessed October 22, 2026.
23. President Honors Recipients of the Presidential Medal of Freedom. The White House (archived), George W. Bush administration. 2005-11-09. accessed October 22, 2026.
24. 2013 QEPrize winners: The Internet and the World Wide Web. Queen Elizabeth Prize for Engineering Foundation. accessed October 22, 2026.
25. IEEE Medal of Honor Goes to Vint Cerf. Joanna Goodrich, IEEE Spectrum. 2023-01-31. accessed October 22, 2026.
26. RFC 9112: HTTP/1.1. R. Fielding, M. Nottingham and J. Reschke (eds.), Internet Engineering Task Force, RFC Editor. 2022-06. accessed October 22, 2026.
27. RFC 9114: HTTP/3. M. Bishop (ed.), Internet Engineering Task Force, RFC Editor. 2022-06. accessed October 22, 2026.
28. Free Pool of IPv4 Address Space Depleted. Number Resource Organization. 2011-02-03. accessed October 22, 2026.
29. RFC 8200: Internet Protocol, Version 6 (IPv6) Specification. S. Deering and R. Hinden, Internet Engineering Task Force, RFC Editor. 2017-07. accessed October 22, 2026.

Web Building Encyclopedia. First published October 22, 2026. Last reviewed October 22, 2026. Every fact on this page is linked to a source we opened. Spotted an error? Write to [email protected].