What is PPP?
PPP (Point to Point Protocol) is a network protocol that allows data communication between two network points or entities. PPP was proposed as a standard in 1989 by IETF (Internet Engineering Task Force) and become a working standard in 1994.
PPP is mostly use by ISPs (Internet Service Provides) to enable dial up connection to the Internet.
PPP uses LCP (Link Control Protocol) to establish a session between user’s computer and an ISP. LCP determines whether the link is acceptable for data transmission.
PPP supports three types of user authentication protocols: PAP, CHAP, and EAP.
PAP (Password Authentication Protocol) is an access control protocol that uses to authenticate user’s password on the network access server. The network access server will request password from client machine and send the retrieved password to authentication server for verification. PAP is least secure because password is not encrypted in transmission.
CHAP (Challenge Handshake Authentication Protocol) is similar to PAP, but it has more unique characteristics. Instead of requesting password, the network access server sends a challenge message (random value) to the client machine. Then client machine will encrypt the challenge message with user’s password and send back combination to access server. If user’s response is a match, the password is considered as authentic. CHAP is moderately secure.
EAP (Extensible Authentication Protocol) is believed as an authentication framework used by a number of secure network protocols. EAP is mostly used on wireless network authentication.