Binary package “portslave” in ubuntu karmic

Terminal server that does PPP and authenticates via RADIUS

 This package provides a program named portslave which will use AT commands
 to answer a modem when it rings. It will then display a login: prompt at
 which the user can enter a user-name and password. If the user sends PPP
 data then portslave will run it's own pppd instead and authenticate the user
 via PAP. When the user-name and password are received they will be verified
 via a RADIUS server.
 .
 At the end of the call the accounting data will be written to the RADIUS
 server.