15.1. Synopsis

If you are connecting to the Internet via modem, or wish to provide dial-up connections to the Internet for others using FreeBSD, you have the option of using PPP or SLIP.

This chapter covers three varieties of PPP; user, kernel, and PPPoE (PPP over Ethernet). It also covers setting up a SLIP client and server.

The first variety of PPP that will be covered is User PPP. User PPP was introduced into FreeBSD in 2.0.5-RELEASE as an addition to the already existing kernel implementation of PPP.

You may be wondering what the main difference is between User PPP and kernel PPP. The answer is simple; user PPP does not run as a daemon, and can run as and when desired. No PPP interface needs to be compiled into their kernel; it runs as a user process, and uses the tunnel device driver (tun) to get data into and out of the kernel.

From here on out in this chapter, user ppp will simply be referred to as ppp unless a distinction needs to be made between it and and any other PPP software such as pppd. Unless otherwise stated, all of the commands explained in this section should be executed as root.