FLI4L (flexible internet router for linux, formerly isdn floppy for linux ) is an actively developed since 2000 Linux distribution whose main task is to provide a router. The distribution can be run from a floppy disk and was created with the aim of a simple configuration and support for older hardware. FLI4L can route between Ethernet and ISDN, UMTS, DSL, or between two Ethernet networks. Fli4l has its own stand at the Chemnitz Linux Days.

Requirements, and Supported Hardware / protocols

FLI4L based on the Linux kernel. The documentation is very extensive. It will be for the installation requires no knowledge of Linux. However, basic knowledge of networking should be available.

The hardware requirements for FLI4L are low, a 486 with 16 MiB RAM and ( depending on configuration) one to two network cards are perfectly adequate. A hard drive is not required, but can be of FLI4L also be used. Since version 3.0.0 offers FLI4L the ability to reproduce a working installation using card reader directly to a CF card, which in turn can be operated with a CF adapter in the IDE slot. Also supported is the direct creation of an ISO image to the operation of CD and DOC / DOM for embedded systems.

Since version 3.2 USB2Serial adapter, Intel and Ralink WLAN cards are supported by the standard kernel.

Since version 3.6 UMTS and IPv6 are supported, with the Linux kernel is 2.6.32 used.

FLI4L can be configured via text files on Linux, Unix and Windows. In addition FLI4L offers the possibility of connections over the Internet or Wireless LAN using OpenVPN or PPTP ( Poptop ) to encrypt.


There are two development branches of FLI4L, a stable and a development version.

The stable version 3.6.2 is based on a kernel 2.6 series and also includes virtualization using Xen. USB and Wi-Fi are widely supported, as well as more recent embedded hardware such as ALIX, Soekris and the Epia series.

The development version ( tarball version ) uses the kernel 3.xy series.

Optional packages

FLI4L pursuing a modular system of so-called OPT packages. Only the software packages for options required to be downloaded and unzipped into the directory tree to create the individual configuration. To extend the basic functions is a wide range of applications in the so-called OPT- database, such as optional packages are integrated to volume observation or a FLI4L can act as a print server. Even our own developments are possible by this method easy and can be made available on the database with other readers.

Control of FLI4L

A FLI4L router can be browser-based controlled and monitored via a web interface. In addition, available as an alternative, the program Imonc (ISDN Monitor Client ) for Windows and Linux ( GTK ) is available, which also allows a great deal of control and also allows a remote-controlled update the router software.

The PC world offers since 2010 a configuration program for FLI4L download for free, with the can be created with Windows operating system a boot disk on a PC.

Other Linux distributions for old PCs

  • Vector Linux Comparable to Desktop Light Linux
  • Damn Small Linux A live CD for resource-poor computer
  • Puppy Linux is another live CD for older PCs
  • M0n0wall firewall and router ( FreeBSD based)
  • IPFire firewall and router ( based on LFS)
  • IPCop firewall and router ( based on LFS)