Point-to-Point Tunneling References

Compiled by Tina Bird, Moderator, VPN Mailing List

Last modified: 06 August 1999

Microsoft Documentation

  • Microsoft's overview of PPTP functionality.
  • Windows Remote Access Security describes the security features of PPTP and provides information on planning your deployment.
  • Understanding Point-to-Point Tunneling Protocol
  • Using Point-to-Point Tunneling Protocol
  • FAQ about Microsoft VPN Security
  • General Comments

  • Russ Cooper's original summary of PPTP, addressed to the Firewalls@Greatcircle.com mailing list in November 1997. Mostly addresses problems with session key generation and weak authentication mechanisms.
  • Aleph One's posting to Firewall-Wizards about crypto vulnerabilities in PPTP. Not quite so polished as the Counterpane documentation, but valuable.

  • In Defense of PPTP, a response to criticisms of Microsoft's PPTP implementation (and how the NTS implementation avoids those problems).
  • PPTP entry from the VPN FAQ.
  • The Counterpane PPTP Analysis

    Bruce Schneier and Mudge identify several major flaws in the Microsoft implementation of PPTP, June 1998.
  • Index
  • Press Release
  • Cryptanalysis
  • Frequently Asked Questions
  • Cryptanalysis of Microsoft;s PPTP Authentication Extensions (MS-CHAPv2)