Thinking outside the (server) box with Linux

Welcome to the first Network World Fusion Focus newsletter on Linux in the enterprise. With the mountains of information available about Linux, it can be hard for network professionals to keep up with Linux news that is fresh and relevant to their jobs. Here each week, you will find Linux industry news, tips and examples of how Linux is being used in enterprise networks. Jumping right in, this week's topic will focus on how Linux can be used to turn an old PC into a network router.

When people talk about a Linux box, what generally comes to mind is either a server or client machine running some distribution of Linux. One way for users to use Linux outside "the box" is with the Linux Router Project's distribution of the operating system.

The Linux Router Project (LRP) is a microdistribution of Linux (it fits on a 1.44M byte floppy) that can be used along with some extra hardware to turn a variety of low-end PCs into practical, useable network gear. Additionally, as with most Linux distributions, the software is free.

A variety of different network devices can be put together using LRP. For instance, using just an Intel 486 PC with a floppy drive, 12M bytes of RAM and at least two network interface cards, LRP can be used to assemble a 10M bit/sec Ethernet router. For higher speeds, a Fast Ethernet router can be assembled with a simple Pentium 100 or higher, along with 16M bytes of RAM and 10/100M bit/sec network interface cards. LRP can also be configured as a secondary Domain Name System firewall, a Remote Authentication Dial-In User Service and a WAN router with DSU functionality. LRP routers support standard routing protocols, such as Routing Information Protocol and Open Shortest Path First. Advanced routing protocols are also supported, such as IPX for NetWare networks and Token Ring.

Building a Linux router out of spare parts can be useful when setting up a testing environment that requires the simulation of live router traffic. It's also more practical than disconnecting your live commercial routing equipment for use in testing purposes. LRP can also be put into a live production environment as a way to add extra routers to a network for a minimal cost.

Because Linux routers can be built with standard PC components, the materials to build one are likely sitting in a storage room or back closet somewhere in your office. LRP is a completely free, open source operating system - so if you can program, you can add functions such as Multi-protocol Label Switching and load balancing to the router by writing customized code.

If you are not a Linux hacker, odds are someone else has already written the code for these types of functions. Start at www.linuxsupportline.com to find these kinds of modules. As with many free software products, your best source of support for LRP will be the Web. An extensive list of FAQs and tips on using LRP can be found at www.linuxrouter.org/faq.

Since LRP is developed and distributed mostly by volunteers, download access to the software is not always very fast. The easiest way to get it is to log on to www.linux-howto.com, which has a search engine for Linux documentation and free distributions. Type in "Linux Router" in the search field, and it will let you choose what geographical region to download the LRP software and source code from for optimal speed. You can also try several of these mirror sites to download LRP:

ftp://ftp.cpwright.com/linux-router/
ftp://lrp.rutgers.edu/pub/linux/distributions/linux-router/
ftp://sunsite.unc.edu/pub/Linux/distributions/linux-router/
ftp://ftp.xtdnet.nl/pub/linux/linux-router/
ftp://sunsite.ktu.lt/pub/linux/distributions/linux-router/
ftp://mirror.aarnet.edu.au/pub/linux/linux-router/
ftp://ftp.clear.net.nz/pub/linux-router/
ftp://mailtrans.sote.hu/linuxrouter/
ftp://ftp.di.fct.unl.pt/pub/linux/linux-router/
ftp://ftp.wipol.uni-bonn.de/pub/mirror/ftp.linuxrouter

Phil Hochmuth is a Network World Senior Writer and a former systems integrator. You can reach him at phochmut@nww.com.

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