Feinler became principal investigator for the ARPANET Network Information Center, a role she held for over a decade.
In 1973, Elizabeth Feinler became the principal investigator for the ARPANET Network Information Center (NIC), a position that would define her career and cement her legacy as one of the internet's foundational architects. In this role, she led the team responsible for creating and maintaining the directory and naming services that allowed the rapidly growing network to function coherently.
Under her leadership, the NIC developed the first host-naming registry, precursor systems to what would become the WHOIS directory service, and foundational protocols for organizing internet resources — work that would directly inform the later creation of the Domain Name System (DNS). Feinler and her team were responsible for assigning and tracking network addresses and host names before automated systems existed, doing much of this work manually in the network's early years.
Her leadership extended beyond ARPANET; she later served the Defense Data Network Network Information Center (DDN NIC) as well, continuing to manage critical naming and directory infrastructure as the network evolved from a research project into essential defense and civilian infrastructure.
This appointment represents one of the earliest instances of a woman leading a technical function so central to what would become the global internet. Feinler held this pivotal role for roughly 16 years, overseeing the transition from a small research network to the burgeoning system that gave rise to top-level domains like .com, .gov, .edu, .mil, .org, and .net.