Chapter 4: Point-to-Point-Protocol Commands:
encapsulation ppp | Sets PPP as the encapsulation method used by a serial or ISDN interface.
ppp authentication | Enables Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP) or both, and specifies the order in which CHAP and PAP authentication are selected on the interface.
ppp chap hostname | Creates a pool of dialup routers that all appear to be the same host when authenticating with CHAP.
ppp chap password | Configures a password that will be sent to hosts that want to authenticate the router. This command limits the number of username/password entries in the router.
ppp pap sent-username | Enables remote PAP support for an interface and uses sent-username and password in the PAP authentication request packet to the peer.
show interfaces | Displays statistics for all interfaces configured on the router or access server.
username password | Specifies the password to be used in CHAP caller identification and PAP.