The PPP Kernel Module:

Chapter 1 showed the kernel messages that are displayed when the serial drivers are installed. Similarly, when PPP is compiled into the kernel, messages about PPP are displayed during startup, as in this Caldera example:

$ dmesg | grep PPP
PPP: version 2.2.0 (dynamic channel allocation)
PPP Dynamic channel allocation code copyright 1995 Caldera, Inc.
PPP line discipline registered.


If PPP is installed by your kernel, you're ready to run the PPP daemon. On most systems, however, the kernel component of PPP is not compiled in the kernel. If it isn't, you must install the loadable module manually.The modprobe command could be used to install the PPP kernel modules. For example, modprobe ppp_async would load the ppp_ async.o module, the ppp_generic.o modules upon which it depends, and the slhc.o module upon which ppp_generic depends. This would provide the kernel modules required by PPP.

Different Linux distributions use different tools for maintaining the modules list. All, however, provide the modprobe commands for you to specify that PPP modules should be included in the kernel at startup.