What RFCs describe the PPP protocol?
The current implementation of PPP is a mixture of several. The major portion of the PPP code is written against the RFCs 1331 and 1332. These RFCs were later obsoleted. 1331 was replaced by 1548 and that, in turn, was obsoleted by 1661 six months later. Most implementations of PPP will be happy to talk to the Linux PPP code. A complete list is in the PPP faq. [to quote the FAQ document]: All of 1134, 1171, and 1172 (and 1055, for that matter 🙂 have been obsoleted. They’re interesting only if you want to debug a connection with an ancient PPP implementation, and you’re wondering why (e.g.) it asked you for IPCP option 2 with a length of only 4, and Compression-Type 0x0037. (There’s a lot of that still running around – be careful out there.) Linux PPP will automatically detect this condition and compensate for it.
