Tenable's CSO Marcus Ranum was quoted in an article from SC Magazine titled "Industry pioneers". In it Marcus gives us some insight into how he perceives his accomplishments:
“I like to think of myself as a filter for good ideas.”
We also get some insight as to how he came up with the idea for building the world's first firewall:
The firewall was really born on a day in 1986 when Ranum, then a network administrator at Johns Hopkins University, noticed something strange: Someone was able gain access to an MRI machine via a Sun Workstation default configuration. Nothing malicious happened, but Ranum knew right then that big problems weren't far off. “People were connecting to the internet and they had no idea what they were doing,” he recalls. Not long after, he built the first commercial-grade firewall for Digital Equipment Corp. and later, the White House. A few years later, he was among the first to market intrusion detection systems. “A lot of my career has consisted of moving ideas from the research world into the commercial world,” says Ranum, who turns 47 this month. “I like to think of myself as a filter for good ideas.” But don't count on any new inventions from him. Today's development tools lead to too many bugs: “I'm still using coding models from the early 80s,” he says.
Marcus is in good company too, others highlighted in the article include Bruce Schnier, Dan Geer, and Whitfield Diffie and Martin Hellman.