PAP provides a simple method for a remote node to establish its identity, using a two-way handshake. After the PPP link establishment phase is complete, a username/password pair is repeatedly sent by the remote node across the link until authentication is acknowledged or the connection is terminated.

PAP is not a strong authentication protocol. Passwords are sent across the link in clear text and there is no protection from playback or repeated trial-and-error attacks. The remote node is in control of the frequency and timing of the login attempts.

Web Links Configuring and Troubleshooting PPP Password Authentication Protocol (PAP) http://www.cisco.com/en/US/tech/tk713/ tk507/technologies_tech_note09186a 0080093c6f.shtml