The Point-to-Point Protocol (PPP) provides a standard way to establish a
network connection over a serial link.  At present, this package supports
IP and the protocols layered above IP, such as TCP and UDP.

This software consists of two parts:
  - Loadable Kernel module, which establishes a network interface and
  passes packets between the serial port, the kernel networking code and
  the PPP daemon (pppd).
  - The PPP daemon (pppd), which negotiates with the peer to establish the
  link and sets up the ppp network interface.  Pppd includes support for
  authentication, so you can control which other systems may make a PPP
  connection and what IP addresses they may use.

This version is patched to support MPPE:
  MPPE - Microsoft Point-to-Point Encryption uses rc4 (40 or 128 bit) as a
  bi-directional encryption algorithm.  The keys are based on your MS-CHAP
  authentication info, so you must use chapms or chapms-v2.

MPPE is NOT a particularly secure mode of operation.  For maximum possible
security using MPPE, it is advised in the RFC's to use the highest mode of
encryption that is legal, and to enable stateless mode (which renogotiates
keys with every packet).  Even with these precautions, MPPE is not very
secure, but anything is better than nothing, right?