An obscure Florida company discreetly announced to the world’s computer networks a startling development: It now was managing a huge unused swath of the Internet that, for several decades, had been owned by the U.S. military. The company, Global Resource Systems LLC, kept adding to its zone of control. Soon it had claimed 56 million IP addresses owned by the Pentagon. Three months later, the total was nearly 175 million. That’s almost 6 percent of a coveted traditional section of Internet real estate — called IPv4 — where such large chunks are worth billions of dollars on the open market. Global Resource Systems founded in September 2020 and has no publicly reported federal contracts and no obvious public-facing website. The company’s address in Plantation, Fla., outside Fort Lauderdale, is a shared workspace in an office building that doesn’t show Global Resource Systems on its lobby directory. The only announcement of Global Resources Systems’ management of Pentagon addresses happened in the obscure world of Border Gateway Protocol (BGP) — the messaging system that tells Internet companies how to route traffic across the world. The change is the handiwork of an elite Pentagon unit known as the Defense Digital Service, which reports directly to the secretary of defense. The DDS bills itself as a “SWAT team of nerds” tasked with solving emergency problems for the department and conducting experimental work to make big technological leaps for the military. Created in 2015, the DDS operates a Silicon Valley-like office within the Pentagon. Brett Goldstein, the DDS’s director, said in a statement that his unit had authorized a “pilot effort” publicizing the IP space owned by the Pentagon. The specifics of what the effort is trying to achieve remain unclear. The Pentagon program that delegated management of a huge swath of the Internet to a Florida company in January 2021— just minutes before President Donald Trump left office — ended as mysteriously as it began, with the Defense Department retaking control of 175 million IP addresses in September 2021. Parts of the Internet once managed by Global Resource Systems, the Pentagon said, now were being overseen by the Department of Defense Information Network, known by the acronym DODIN and part of U.S. Cyber Command, based at Fort Meade. But the Pentagon statement shed little new light on exactly what the pilot program was doing or why it now has ended. An analysis of traffic flowing through the Internet addresses once controlled by Global Resource Systems are still leading to the same place as they have for most of the year — a computer router in Ashburn, Va., a major hub of Internet connections for government agencies and private companies — despite the official resumption of Pentagon control.