As the fifth employee of Sun Microsystems and founder of Cygnus Support, he became wealthy enough to retire early and pursue other interests. He is also one of the founders of the Electronic Frontier Foundation based in San Francisco.[3]
He is a frequent contributor to free software, and worked on several GNU projects, including maintaining the GNU Debugger in the early 1990s, initiating GNU Radio in 1998, starting Gnash media player in December 2005 to create a free software player for Flash movies, and writing the pdtar program which became GNU tar. Outside of the GNU project he founded the FreeS/WAN project, an implementation of IPsec, to promote the encryption of Internet traffic. He sponsored the EFF's Deep CrackDES cracker, sponsored the Micropolis city building game based on SimCity, and is a proponent of opportunistic encryption.
Gilmore co-authored the Bootstrap Protocol (RFC 951) with Bill Croft in 1985. The Bootstrap Protocol evolved into DHCP, the method by which Ethernet and wireless networks typically assign devices an IP address.
On October 22, 2021, EFF announced that they had removed Gilmore from the Board following a governance dispute.[4] The details of the dispute were not made public.[5]
Gilmore owns the domain name toad.com, which is one of the 100 oldest active .com domains. It was registered on August 18, 1987. He runs[7] the mail server at toad.com as an open mail relay. In October 2002, Gilmore's ISP, Verio, cut off his Internet access for running an open relay, a violation of Verio's terms of service. Many people contend that open relays make it too easy to send spam. Gilmore protests that his mail server was programmed to be essentially useless to spammers and other senders of mass email and he argues that Verio's actions constitute censorship. He also notes that his configuration makes it easier for friends who travel to send email, although his critics counter that there are other mechanisms to accommodate people wanting to send email while traveling. The measures Gilmore took to make his server useless to spammers may or may not have helped, considering that in 2002, at least one mass-mailing worm that propagated through open relays — W32.Yaha — had been hard-coded to relay through the toad.com mail server.[8]
Gilmore famously stated of Internet censorship that "The Net interprets censorship as damage and routes around it".[9]
^As of June 1, 2023, new.toad.com is still an open mail relay.
^Knowles, Douglas (February 13, 2007). "W32.Yaha@mm technical details". Symantec. Archived from the original on May 24, 2007. Retrieved September 26, 2016. if it cannot connect to the email server listed in that registry key, it will use one of the following: [...21 domain names snipped...], toad.com, [...2 more...]
^ARDC Board of Directors (July 18, 2019). "AMPRNet Address Sale". Amateur Radio Digital Communications. Archived from the original on July 19, 2019. Retrieved July 20, 2019. The sale amounts to some millions of dollars, which will be used in the furtherance of ARDC's continuing public benefit purpose.... The uppermost 1/4 of the former AMPRNet address space (44.192.0.0/10) has been ... sold to another owner ... over 12 million IPv4 addresses remain
^Kantor, Brian; Karn, Phil; Claffy, K. C.; Gilmore, John; Magnuski, Hank; Garbee, Bdale; Hansen, Skip; Horne, Bill; Ricketts, John; Traschewski, Jann; Vixie, Paul (July 20, 2019). "AMPRNet". Amateur Radio Digital Communications. Archived from the original on July 19, 2019. Retrieved July 20, 2019. in mid-2019, a block of approximately four million consecutive AMPRNet addresses denoted as 44.192.0.0/10 was ... sold to the highest qualified bidder at the then-current fair market value ... leaves some twelve million addresses ... The ARDC Board of Directors ... John Gilmore, W0GNU
