radiusd-livingston binary package in Ubuntu Trusty amd64

 RADIUS is an AAA (authentication, authorization and accounting) protocol for
 managing client access to network services, and is described by RFCs 2865 to
 2869. This version of the RADIUS server is from Lucent Technologies Inc.,
 formerly known as Livingston Enterprises Inc.
 .
 Some Internet Service Providers (ISPs) require a username and password to be
 given on connection. Before access to the network is granted, this
 information is passed to a Network Access Server (NAS) device over the
 link-layer protocol and then to a RADIUS server over the RADIUS protocol. The
 RADIUS server checks that the information is correct using authentication
 schemes like PAP, CHAP or EAP. If accepted, the server will then authorize
 access to the ISP's system and select an IP address, L2TP parameters, etc.
 .
 RADIUS is also commonly used for accounting purposes so that the users can be
 billed accordingly.

Source package