3Com Router Command Reference Guide — V1.00There are two PPP authentication methods: PAP and CHAP. PAP (PasswordAuthentication Protocol) is a twice handshake authentication protocol, which transfersthe password in plain text. CHAP (Challenge Handshake Authentication Protocol) is athree-times handshake, which transfers not the password in the network but theusername. Comparatively, CHAP authentication has the better secrecy, and is moresecure and reliable.At an asynchronous dialer interface, you can perform authentication only on incomingcalls instead of outgoing calls. This configuration is necessary when the router servesas an access server.In addition, the defined AAA authentication method is used. CHAP or PAP is just anauthentication process. The success of the authentication is decided by AAA, whichcan authenticate based on the local authentication database or AAA server.For related commands, see local-user, ppp chap user, ppp pap local-user, aaaauthentication-scheme ppp.Example# Authenticate the remote device by PAP on interface Serial0.[3Com-Serial0]ppp authentication-mode pap1.1.5 ppp chap passwordSyntaxppp chap password { simple | cipher } passwordundo ppp chap passwordViewInterface viewParameterpassword: Password transmitted.simple: Display the password plain text.cipher: Display the password in cipher text.DescriptionUsing the ppp chap password command, you can configure the default CHAPpassword when the local router authenticates the remote router. Using the undo pppchap password command, you can disable the configuration.By default, CHAP password is null.10
