4.6.1. MPPC protocol

Mpd implements Microsoft Point-to-point compression (MPPC) CCP subprotol. To enable it, 'mppc' option should be enabled at the CCP layer.

MPPC CCP subprotocol consists of MPPC compression and MPPE encryption parts. To make MPPC CCP actually do something you should enable some of them using options below.

set mppc accept option ...

set mppc deny option ...

set mppc enable option ...

set mppc disable option ...

set mppc yes option ...

set mppc no option ...

These commands configure various MPPC options.

compress

Enables MPPC compression. This is the only compression method supported by Microsoft Windows RAS.

Note: This option requires ng_mppc node to be built with compression support, which is disabled by default, requiring external compressor code. Open-source implementation of this code, based on RFC2118, could be found at http://mavhome.dp.ua/MPPC/. But MPPC compression algorithm itself covered by US patent, so you may need to contact Hi/Fn Inc. to obtain their proprietary implementation. If kernel support is not detected, compression will not be negotiated. Use 'show version' command to get actual status.

The default is disable.

e40

Enables 40-bit MPPE encryption.

The default is disable.

e56

Enables 56-bit MPPE encryption.

The default is disable.

e128

Enables 128-bit MPPE encryption.

Note: in order for MPPE encryption to work, MS-CHAPv1 or MS-CHAPv2 auth is mandatory, because the MPPE keys are generated using the authentication results. If MS-CHAP auth is not used by link, encryption will not be negotiated.

The default is disable.

stateless

Enables stateless mode. This mode requires more CPU time and is somewhat less secure, but allows faster recovery in the face of lost packets.

The default is disable.

policy

If enabled, Mpd uses the MPPE-Types and MPPE-Policy info from the authentication backend.

The default is disable.