At my very core, I’m really just a geek.

A computer-building, Neuromancer-reading, software writing, hardware hacking, hopelessly passionate geek. That’s been true since I took my family’s TV apart as a kid. My dad, always a sweet and patient man, just asked if I could put it back together again and seemed glad (and relieved) when I managed to do just that.

I’ve always had a natural curiosity in how big, complex systems work. That curiosity really started everything for me, and in a lot of ways, it’s what has propelled me to where I am today.

And that’s why I’m writing this: After two decades of pouring my heart and soul into creating Snort, founding Sourcefire and then doing my small part to help lead the best Cybersecurity team in the world at Cisco, I’m ready to take on a new challenge.

I’ll touch more on that in a bit, but first I wanted to reflect a bit on what led me to this moment and what I’ve learned along the way.

My journey and career are largely associated with one technology, but my story — my success — is really about people.

Sourcefire in September 2001 with our three employees at the time — John Pavlick, Bill Sento, and Mike Forostiak. This was a couple weeks prior to our first-customer ship of Sourcefire’s first product!

When I first released Snort 20 years ago, the idea of open-source software was emergent and untrusted in the larger world of software development. This concept that software should be created by and for communities of users rather than corporations was an approach that was seen as radical by many.

Snort went from its first lines of code to being the most popular intrusion detection software in the world in less than two years, producing a thriving community of users like Erek Adams and contributors like Fyodor Yarochkin that helped shape both me and my project.

I worked on Snort every moment I could spare and it reflected the power of the open-source development methodology, a virtuous feedback cycle that resulted in software that people wanted to use and that worked as they expected. Along the way, I met a huge number of people and was exposed to the marketplace of ideas around security — a marketplace in which I became an enthusiastic contributor.

Just after Snort celebrated its second birthday I decided to do something that most people didn’t think was possible: I started a product company around my open-source project.

John Pavlick at Sourcefire HQ (aka my living room) in October 2001 with my then 3-month-old daughter, Molly.

I knew I had developed an incredibly popular, free security technology and I thought I had a business model that would work to get people to want to pay for it. As my team at Sourcefire and I developed enterprise-grade offerings around it, I felt sure that we could produce very competitive products and build stuff that was fundamentally better than our competitors.

But what I learned quickly was that the best products don’t always win. In the world of enterprise security companies, many times it’s the best go-to-market strategy in addition to solid products that win. And on that front, I needed help — and that was going to require a lot of money.

Early on, a lot of VC’s didn’t see how we could make money with Snort. After all, how do you make money selling something that’s free? For this to work, I had to rely on a different kind of business model — a freemium model relying on offering a free core product with enterprise-grade infrastructure built on top of it — and a lot of investors told me straight up I would never make a dime trying that approach.

Fortunately, and this is something that’s helped me quite a bit in my career, I’m pretty good at kind of dismissing doubters.

If you’re trying to do something new or ambitious, there’s plenty of people willing to tell you why it won’t work. I never let those people discourage me, I just figured their preexisting experiences and biases made what I was doing seem deeply foreign to them. In the long run, if you want to be successful when you’re doing something really new it’s more important to find people who know things that you don’t and are willing to put their belief in what you’re trying to do. Those are the people you actually need in order to turn a bunch of “crazy” ideas into a business.

One of those people for me early on was my first angel investor Stephen Northcutt.

As the CEO at the SANS Institute, Stephen truly was an expert in this field, and the fact that he saw potential in my company meant more to me than anyone else’s doubt ever could. He gave me $100,000 out of his own pocket to pursue my dream, and with his investment, I ran the entire company for ten months on a shoestring budget. But it was during that ten months that I learned so many crucial lessons that ended up propelling Sourcefire forward.

Andrew Baker, Sourcefire’s fourth employee, cutting code on my kitchen table in front of the stack of boxes containing the hardware that would become our first order, September 2001. Special guest appearance by my cat, Olivia.

I was feeling pretty good about being on the right track with my ideas but suddenly I found myself as a technologist who was going to need a lot of help from a variety of people if this thing was going to be successful. I needed people who knew a lot more about the business of doing business than I did.

I needed someone like Paul Volkman.

Paul was the first actual sales guy I ever interviewed to work for Sourcefire. I still think back fondly about the first time we met was at my office.

(By office, I mean kitchen table — for the first year we ran the entire company from my home.)

At Sourcefire’s first office in Columbia, MD with Molly on my lap. February 2002.

So there I was, bouncing my six-month-old daughter on my knee as I sat across from this guy who could have found a job at plenty of other more established businesses. And even though he had plenty of reasons to dismiss my whole operation as having no money, no clue, and no hope — and honestly, in that situation, who could have blamed him? — instead Paul did something pretty incredible: He believed in me.

Not only that, he ended up telling all of his friends from his previous company about why they should believe in me too. And it was those people who Paul reached out to that would form what became the core executive team of Sourcefire — the CEO Wayne Jackson, COO Tom McDonough, and four people (three Johns and Allen) who formed the core of our sales leadership team and stuck with the company through its entire run.

I was also lucky to be connected to people like Frank Marshall, a Silicon Valley vet and former VP of Core Products at Cisco during their hyper-growth phase who was the very first west coast person to take me seriously. He pointed Tim Webb at me, a partner at an east coast boutique venture firm called Inflection Point that took the leap along with Frank to lead the first tranche of the Series A.

Once seasoned pros and institutional money joined the party, things changed a lot for me.

It was that injection of talent and money that afforded me the opportunity to focus on the things I was good at, rather than spending so much time worrying about the things I wasn’t. Being able to leverage the expertise of the people who joined the company alongside the functional security experts we had on board is what really turned my idea into a company.

That’s truly why I believe my story is one about people. Yes, I had a product I greatly believed in, but without all these different individuals from various backgrounds coming together with one purpose, it wouldn’t have mattered.

And that’s why I’m so grateful to all of them, and always will be.