- PAP (Password Authentication Protocol)
- CHAP (Challenge/Handshake Authentication Protocol)
- MSCHAP (Microsoft CHAP) is a variation.
If the server is requesting MS CHAP authentication, you will see lines like:
rcvd [LCP ConfReq id=0x2 <asyncmap 0x0> <auth chap 80> <magic 0x46a3>The critical information here is auth chap 80. In PPP source tarball, there is a file README.MSCHAP80 that discusses this. In order to use MS CHAP, you will need to recompile pppd to support this.
- The first point to note about PAP and CHAP is that they are designed to authenticate computer systems not users: once your computer has made its PPP connection to the server, ANY user on your system can use that connection.
/etc/ppp/pap-secrets /etc/ppp/chap-secretsThey must be owned by user root, group root and have file permissions 740 for security.