We've been around the block a time or two.

History in tech

A timeline of important events since the dawn of cybersecurity, and some of our team's contributions across the years.
1988-2023
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1988

November 9, 1988

Robert Morris Jr. Internet worm unleashes fury on the world — Rule4 co-founder participates in forensic investigation. This is the dawn of Internet cybersecurity.
1989

July 1, 1989

“UNIX System Administration Handbook,” 1st edition is published — a Rule4 co-founder is a collaborator and technical reviewer.
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1989

1989

Rule4 co-founder rewrites parts of popular UNIX/Linux tool sudo. See more about the History of Sudo.
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1989

September 1, 1989

A team from University of Colorado Boulder (including a Rule4 co-founder) installs a network for the Princeton University Computer Science Building, the first purpose-built computer science building in the U.S. with high-speed networking to every desktop.
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1990

July 4, 1990

4.3BSD-Reno UNIX is released, and includes mostly AT&T-free kernel source and MIPS processor support by Rule4 co-founder — code that lives on today in every iPhone, Android, and MacOS system.
1991

January 1991

Berkeley Software Design, Inc. (BSDI) is founded, including a Rule4 co-founder. Mission: Make the first fully commercial, non-AT&T UNIX.
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1991

January 1991

XOR, Inc. is founded by Rule4 co-founder.
1991

1991

Colorado SuperNet (non-profit) contracts with XOR to establish local dial-up Internet in all Colorado calling areas.
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1992

1992

Rule4 co-founder discovers a hacker in Colorado SuperNet systems; this discovery eventually leads to the arrest and conviction of now-famous industry evangelist Kevin Mitnick.
1992

1992

BSDI, including a Rule4 co-founder, and The Regents of the University of California are sued by AT&T Unix System Laboratories for intellectual property issues stemming from alleged use of licensed UNIX source code.

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1993

1993

Rule4 co-founder enters Ph.D. computer science program at CU Boulder focused on distributed systems and machine learning.
1994

1994

Rule4 co-founders establish community cooperative non-profit Internet provider, Colorado Internet COOP. Becomes largest commercial Internet-bandwidth provider in Colorado (for a time).
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1994

1994

AT&T/BSDI/UCB lawsuit is settled favorably, but BSDI and BSD UNIX are mortally wounded. Linux has stepped into the void created by AT&T hugging its child to death.
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1995

1995

XOR launches first real-time Internet rental car booking system (alamo.com) against claims that it “couldn’t be done.” Saves Alamo from the brink of bankruptcy and ignites the Internet as the way to book travel.
1995

1995

XOR designs and produces first enterprise monitoring platform olympics at Enterprise Management Summit in Dallas, Texas.
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1995

1995

“Unix System Administration Handbook,” 2nd edition is released. A Rule4 co-founder is a primary author.
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1996

1996

XOR launches wholefoods.com, the online home of Whole Foods Market, and the first Internet full-service holistic foods purveyor.
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1997

November 17, 1997

A legend is born: qwest.com domain is first registered by one of Rule4’s current leaders. Qwest goes on to swallow Baby Bell (RBOC) US West in 2000.
1999

1999

XOR is acquired by a Chicago private-equity firm, acquires multiple other web consulting firms to become one of the largest e-commerce powerhouses in the U.S.
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2000

2000

“UNIX System Administration Handbook,” 3rd edition is released.
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2001

2001

Founding of AppliedTrust, one of the first dedicated cybersecurity consultancies. “You’ll never be able to find enough security business,” said one mentor.
2002

2002

XOR is acquired by credit-scoring firm FICO.
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2002

2002

“Linux Administration Handbook,” 1st edition is released.
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2006

2006

“Linux Administration Handbook,” 2nd edition is released.
2009

2009

AppliedTrust wins coveted Colorado Technology Association APEX Award as Service Company of the Year.
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2010

2010

“Unix and Linux System Administration Handbook,” 4th edition is released.
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2011

2011

Rule4 co-founders create “Boulder Is for Startups” campaign acknowledging Boulder’s growing tech dominance.
2012

2012

Rule4 co-founder Dan Mackin is named Chief Operating Officer of AppliedTrust.
2015

2015

AppliedTrust is acquired by industry-leader ViaWest.
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2017

2017

ViaWest + AppliedTrust is acquired by Peak10 and changes name to Flexential but remains in technology/datacenter industry.
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2017

2017

“Unix and Linux System Administration Handbook,” 5th edition is released, includes two co-founders of Rule4 as primary authors.
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2018

September 17, 2018

Rule4 is founded.
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2019

2019

Rule4 becomes a Certified B Corporation.
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2020

September 2020

Boulder County names Rule4 one of its “core partners” in an election security community briefing ahead of the 2020 presidential election.
2020

2020

Rule4 wins Startup of the Year award at Boulder Chamber’s Celebration of Leadership.
2021

2021

Rule4 is authorized as a Registered Provider Organization (RPO) by the Cybersecurity Maturity Model Certification Accreditation Body (CMMC-AB).
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2021

February 2021

Rule4 Co-CEO Dan Mackin is chosen as CEO of the Year by the Colorado Technology Association.
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2021

October 2021

Out of 1,100 nominations, Rule4 is chosen as one of 50 Colorado Companies to Watch.
2021

November 2021

Rule4 is ranked #4 on Outside’s list of the 50 Best Places to Work in 2021.
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2022

November 2022

Rule4 makes Top 10 of Outside’s 50 Best Places to Work list for second straight year.
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2023

January 2023

Rule4 named to prestigious tech industry list of best places to work.
2023

February 2023

The Colorado Technology Association names Rule4 the Emerging Tech Company of the Year.
2023

February 2023

Rule4 SVP of Operations wins the Emerging Leader of the Year Award at Colorado Technology Association Summit.

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2023

August 15, 2023

In its first year of eligibility, Rule4 is ranked #2,990 on the prestigious Inc. 5000.
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2023

November 16, 2023

Rule4 is ranked #1 on Outside Magazine’s list of Best Places to Work in 2023.
2024

August 2024

Rule4 teams up with EcoSoul Partners to offset 100% of the company’s carbon impact and 100% of each fox’s personal carbon footprint.