History of the RADIUS Server

Interlink Networks claims in its history, the origins as one of the founders of the RADIUS Server and the RADIUS protocol. Actually, Merit Network, the non-profit that spun out Interlink Networks in 2000, first specified the RFI for what was to become the RADIUS server.

In the early days of dial-up connections, a user dialing into a network had to connect with a computer that asked for a user name and password. Basically, unauthorized access was blocked at dial-in by the back-end computer.

In 1987, Merit Network bid on and was awarded the contract to run the NSFnet by the National Science Foundation. The NSFnet was the backbone for the national Internet and from 1987 until the commercialization of the NSFnet in 1995 Merit was very involved with growing and supporting the Internet. Internally at Merit there were two operational groups, NSFnet group focusing on national networking and MichNet group focusing on statewide networking.

By 1991, as the Internet was becoming more popular, MichNet faced a problem with its dial-up services getting swamped by unregistered users. It turned out that to connect to the Internet, didn't require a user name or password. So rather than connect directly to a computer that could check access credentials, users could dial into the network, access the Internet, and never have to pass user credentials.

To cut down on unauthorized access, Merit drafted an RFI for dial-in support and solicited responses from seven or eight vendors. The requirement to provide distributed dial-in services and remote authentication was a stumbling block for many respondents.

However, Livingston did respond to the RFI was a description of a RADIUS Server. Merit liked the solution and awarded the contract to Livingston which implemented the prototype RADIUS client in their “Portmaster” dial-in server product and created a simple RADIUS server software to support it.

Merit bought and installed Livingston Portmasters and RADIUS server software (which Livingston included for free with the Portmaster hardware) in MichNet. From there, Merit extended Livingston’s RADIUS server to support additional features such as proxying for distributed authentication and support for MichNet’s unique shared dial-in services. Within a year Merit had developed a totally rewritten RADIUS server—the Merit RADIUS Server. The Merit RADIUS Server and its successors (now Interlink Networks’ RAD-Series RADIUS Server) has been used in hundreds of thousands of networks across the world, securing not only dial-up, but wireless and mobile networks as well.

In 1992, the IETF (Internet Engineering Task Force) formed the NASREQ (NAS requirements) working group that was co-chaired by 2 of Merit's engineers. Merit worked with the rest of the industry to guide the RADIUS server through the standards process to create the RADIUS protocol RFC that was issued in 1997. You can read a more extensive account on the History of RADIUS here.

In June 2000, Merit spun off Interlink Networks as it's own business focusing on delivering high performance, highly extensible RADIUS server software for Carriers and ISPs. The RAD-Series RADIUS Server (formerly the Merit RADIUS Server) is used in some of the largest installations by Carriers and ISPs across the world. A great example is KT in South Korea that are controlling access to over 800,000 WiFi access points, ADSL, ISDN, and PSTN for over 6,500,000 users through 13 RAD-Series RADIUS Servers.