OpenSSG is an implementation of the Cisco
Service Selection Gateway, which is available on
IOS devices with the required feature image. It
uses libipq for user-space packet inspection.
Traffic flows of unauthenticated users are
redirected to a SESM (Subscriber Edge Service
Manager), where they are authenticated by
whatever means (an HTTP server with a database
backend, or a telnet server). Upon
authentication, the user is authenticated with a
certain IP and this is sent to the SSG server.
