There is no doubt in my mind that Linux is the best operating system available, and having the source at your fingertips provides enormous leverage. That was reinforced for me after giving an X.25 course recently in Canberra, Australia. I had been unhappy with the ancient X.25 Packet Assembler/Disassemblers (PADs) the class used and thought that we ought to be able to use Linux to demonstrate many of the concepts in the course.

While Linux has good X.25 support, when using X.25 between pairs of Linux systems you have to modify the LAPB driver (to function as a DCE). I felt that made class setup more difficult. On the flight home, I fired up my laptop and modified the LAPB driver to automatically set the appropriate parameter when loading the module with insmod or modprobe. Try doing that with a proprietary operating system!

When I got home, I had everything working, which means that future courses will be able to use Linux with Ethereal to give students hands-on exposure to X.25 using modern tools that they are likely to have available in the office and at home.

Speaking of Ethereal brings me to the topic of this month: Network debugging in a mixed Windows and Linux environment.

Many of us have to deal with Windows, sometimes on a daily basis. When we do, we often have to debug networking problems. It is very helpful to be able to find problems both from Linux and from Windows. This article explores the tools available to us in resolving network problems and observes that the strong similarity in those tools under Windows and Linux means that we can be more effective in both environments.

We will look at the mainstays like ping, traceroute (or tracert), nslookup, and so on. We will also look at Ethereal, as it is available for both Linux and Windows.

Tools common to Linux and DOS

Probably you are all familiar with tools under Linux like ping, traceroute, ifconfig, and so forth. However, the over emphasis on the GUI under Windows leads many people to believe that similar tools are not available for Windows. That is just not true; all you need to do is to fire up a command prompt. Click on Start, Run, enter command under Win9x, or cmd under Windows NT, and then click on Ok. Those same tools are also available as MS-DOS Prompt under Start, Programs. Once you have started a command prompt, a number of tools become available that behave in similar ways to tools under Linux.

First and foremost, there is ping. This command operates a little differently than the Linux ping command. Here is an example:

C:\>ping 10.0.0.6




Pinging 10.0.0.6 with 32 bytes of