Gpppkill
- A program for Linux that ends a ppp connection if it doesn't receive a minimal amount of bytes during a preset time. Latest stable release is 1.0.3, 2000-09-10.
How to Hook up PPP in Linux
- A detailed guide to hooking up a PPP link to an Internet Service Provider (ISP) (2002)
Slirp
- A SLIP/PPP link emulator. Latest stable release is 1.0.17, 2006-01-08.
VPPP - Visual PPP
- A graphical interface to pppd which allows configuring connections to different Internet providers, launching, stopping, and viewing the state of these connections. Latest release is 3.7, 2003-06-29. Site also available in French.