Router on a Floppy

A software router running on Linux, and needing as little as a floppy space isn’t new. Over the years, building and setting up such routers has been simplified. For instance, BBIagent is a small Linux distribution that can be set up to work as a router, without issuing a single Linux command. It can even run on a 386! What’s more, it can be completely set up through a graphical wizard. 

The setup



Set up the machine to be your router. Note that you don’t need a hard disk or an operating system on the machine. It will have two network cards. The first one will be connected to the internal/private network (call it the internal interface) and the second (the external interface) will be connected to the external network or Internet. For our sample setup, we assume the internal network to be with network address 192.168.1.0. Next, we assign a static IP address — 192.168.1.1 — to the internal interface. 

The external interface is connected to the Internet through a router or DSL/ISDN modem.

You need to download a boot image appropriate for the hardware of the router machine. Go to http://www.bbiagent.net/en/download.htm and scroll down to the ‘Create and download a boot image file’ section. Click on ‘Applet’ link, which will launch the BBIagent setup applet. Follow the on-screen instructions, and key in the internal IP address - 192.168.1.1 in our case - and the associated subnet mask (255.255.255.0). Select the CPU type and amount of RAM you have on the router machine. Select the name/model of the network card connected to the internal network. In the dialog window titled ‘Select connection protocol for external network’, select the radio button labeled ‘Ethernet with static IP address’. 

Select the model of the external network card in the next dialog. In the “Enable built-in servers when the router starts up” section, uncheck the option for DHCP server if you have one running on your network. Finally, click on the download button and save the boot image file named BBIagent. img (in say C:\). 

Next, we will need to extract and copy this image onto a floppy. For this, use rawrite utility found on the PCQLinux 7.1 CD1 in the dosutils directory. Insert a formatted floppy in the floppy drive. Switch to dos mode or command prompt. Change to dosutils directory on the CD and type rawrite. When prompted for the disk image file, enter c:\BBIagent.img. For the target diskette drive, enter the drive letter of your floppy drive (usually, a). 

Boot the router machine using this floppy. The only thing left to set up is the IP address to the external interface. This can be done through a Java based graphical interface called BBIagent Explorer. Hop back to a Windows machine and download BBIagent.jar from:

http://www.bbiagent.net/jar/BBIagent.jar

You must have JDK (Java Development Kit) installed on the windows machine. Run BBIagent Explorer as:



java -jar BBIagent.jar -r

For example, in our case it was: java -jar BBIagent.jar -r 192.168.1.1

This will launch the BBIagent explorer and prompt for password. Type in the password BBIagent — the default password that is case sensitive. Click on ‘WAN Connection’ on the left, and then on the ‘Setup’ button on the top. Enter the external IP address, the associated subnet mask, IP address of the gateway device and IP address of a DNS server. When done, click on the button ‘Save to Diskette in Router’. Click on ‘Disconnect’, and then on the ‘Connect’ button on top. Set up the client machines on your network with gateway as 192.168.1.1. 

Now, we have a router running with minimal configuration. You can also set up a firewall and some basic security measures through BBIagent Explorer. BBIagent Explorer provides a graphical view of the traffic, and logs for monitoring the usage of the router. For more information, refer to

http://www.bbiagent.net .

Shekhar Govindarajan