Core issue
Point-to-Point Tunneling Protocol (PPTP) with local authentication works properly, and the user wants to add Microsoft Point-to-Point Encryption (MPPE).
Resolution
MPPE requires MS-CHAP authentication be configured on the PIX Firewall, and that the PC PPTP client supports and is configured for MS-CHAP version 1.
Add the vpdn group group_name ppp encryption mppe {40|128|auto} command to the configuration.
For more information and configuration examples, refer to How to Configure the Cisco Secure PIX Firewall to Use PPTP.
