from Wikipedia, the free encyclopedia
developer fli4l team
License (s) GPL ( Free Software )
First publ. April 2000
Current  version 10/3/19 (February 2, 2020)
Current  preliminary version Tarball version  (weekly)
ancestry GNU / Linux
↳ fli4l
Architecture (s) i386 , X64
Languages) German , English , French

fli4l ( fl exible i nternet router for l inux, formerly fl oppy i sDn for l inux) is an actively developed since 2000 Linux distribution whose main task providing a router is. The distribution can be run from floppy disk and was created with the aim of simplifying configuration and supporting older hardware. fli4l can route between Ethernet and ISDN , UMTS or DSL or between two Ethernet networks.

Requirements and supported hardware / protocols

fli4l is based on the Linux kernel . The documentation is very extensive. No Linux knowledge is required for the installation. However, basic knowledge of network technology should be available.

The hardware requirements for fli4l are low, a Pentium with MMX support, 64 MiB RAM and (depending on the configuration) one or two network cards are sufficient. A hard disk is not required, but can also be used by fli4l. From version 3.0.0, fli4l also offers the possibility of creating an executable installation using a card reader directly on a CF card, which in turn can be operated with a CF adapter in the IDE slot. The direct generation of an ISO image for the operation of CD and DOC / DOM for embedded systems is also supported .

As of version 3.2, the standard kernel supports usb2serial adapters, Intel and Ralink WLAN cards.

From version 3.6 UMTS and IPv6 are supported, whereby the Linux kernel 2.6.32 is used.

Version 3.10 is based on the Linux kernel series 3.16 and, in addition to improved hardware support, also brings improvements in firewall configuration and IPv6 support.

fli4l can be configured under Linux , Unix and Windows via text files. In addition, fli4l offers the option of encrypting connections over the Internet or in WLAN using OpenVPN or PPTP (Poptop).


There are two development branches of fli4l, a stable and a development version.

The stable version 3.10.x is based on a 3.16 series kernel and also includes support for virtualized systems based on Xen and KVM . USB and WLAN are largely supported, as well as more recent embedded hardware such as APU, ALiX, Soekris and the Epia series .

The 4.0 developer version (tarball version) provides Linux kernels of the 4.1 series. Furthermore, it implements a completely newly developed management and configuration of connections (so-called circuits) with which u. a. several WAN connections (e.g. via DSL, ISDN or UMTS) can be operated in parallel.

Optional packages

fli4l is based on a modular system using so-called OPT packages. Only the software packages for the desired options are downloaded and unpacked into the directory tree for creating the individual configuration. A wide range of applications is available in the so-called OPT database to expand the basic functions. For example, optional packages for volume monitoring can be integrated or a fli4l can act as a print server. Using this process, your own developments are also easily possible and can be made accessible to other users via the database.

Control of the fli4l

A fli4l router can be controlled and monitored via a web interface . In addition, available as an alternative, the imonc (Program I SDN Mon itor C lient) for Windows and for Linux ( GTK ) is available, which also allows an extensive control and also allows a remote controlled update the router software.

The PC world has been offering a configuration program for fli4l for free download since 2010, with which a boot disk can be created on a PC with the Windows operating system.

Eisfair (fli4l derivative)

As the fli4l project grew in size over time, the sponsoring association net (t) work (s) eV developed and distributed the Eisfair project , a server distribution with a greater range of functions than planned for fli4l.

Other Linux distributions for old PCs


Web links

Individual evidence

  1. net (t) work (s) eV
  2. Release of the stable fli4l version. Retrieved February 2, 2020 .
  3. a b Last weekly developer version
  4. And so it all started
  5. Do-it-yourself firewall: A firewall can be set up with Linux-based software and the cheapest hardware. Report in PC-Welt 11/2005
  6. ^ Report in c't 08/2008 on heise.de
  7. Floppy disk router fli4l 3.2.0 published on golem.de on March 17th, 2008
  8. Routerdistribution Fli4L supports UMTS and IPv6 on golem.de from May 2nd, 2011
  9. Poptop
  10. The fli4l database for optional packages
  11. Configuration program for fli4l
  12. Eisfair