CHAP: challenge-handshake authentication protocol
DSL: digital subscriber line
IETF: Internet Engineering Task Force
IP: Internet protocol
IPsec: IP authentication and security protocols
MSCHAP: Microsoft CHAP
MPPE: Microsoft point-to-point encryption
PAC: PPTP access concentrator
PAP: password authentication protocol
PPP: point-to-point protocol
PPTP: point-to-point tunneling protocol
RAS: remote-access server
RFC: request for comment
VPN: virtual private network