Authentication protocol for remote access peer SSTP VPN pap chap mschap mschap-v2 pap Authentication via PAP (Password Authentication Protocol) chap Authentication via CHAP (Challenge Handshake Authentication Protocol) mschap Authentication via MS-CHAP (Microsoft Challenge Handshake Authentication Protocol) mschap-v2 Authentication via MS-CHAPv2 (Microsoft Challenge Handshake Authentication Protocol, version 2) ^(pap|chap|mschap|mschap-v2)$ pap chap mschap mschap-v2