Well, that's odd. Here's what I'd check when you boot to HD:
  • 1 - the installed kernel is the same as the CD kernel that you boot (2.4.27 or 2.6.9);
    2 - you're not using the boot parameter (cheatcode) nodhcp;
    3 - during boot, Knoppix gives the message Network device eth0 detected;
    4 - $ dmesg | grep eth0;
    5 - $ cat /proc/net/dev;
    6 - $ cat /etc/sysconfig/(kernel-version)/netcard.
For step (1) you can type $ uname -r to see what kernel is installed. The CD boots with 2.4.27 unless you type knoppix26 - but it doesn't hurt to practice with the command line and use uname when you boot the CD to check stuff.

Step (2) is to make sure Knoppix looks for a router or always-on internet provider. (DHCP is the Dynamic Host Configuration Protocol, which lets something else set your system's internet parameters like IP address.) If you installed a bootloader, nodhcp might show up there. For LILO, for instance, look in /etc/lilo.conf for the line append=.

Step (3) is to make sure Knoppix finds your ethernet hardware (eth0 is the first one - you may have more) and also finds your router or internet provider. The message is one of the last that the Knoppix startup scripts print in color before starting KDE.

If you don't notice it, once you're in KDE you can switch to console 1 by typing all together <CTRL><ALT>F1 and you'll see the last screenful of messages. To get back into GUI mode, type <ALT><left arrow> or go to its default display with <CTRL><ALT>F7.

If Knoppix doesn't give this message, use step (4) as another check for hardware detection. If you type just the command $ dmesg in a terminal window, you'll get an eyeful of boot messages - it's good to look through the whole pile sometimes, and in a terminal window you can scroll up and down at your leisure.

But to cut to the chase, you can instead direct the ouput of dmesg (with the "|" pipe symbol) to the filter grep and tell it to show you any lines that have "eth0" in them.

If (3) gives negative results but (4) is okay, then something is badly wrong with the Knoppix part of your installation. If (4) doesn't turn up either, then something is badly wrong with the Linux part. Either way, I think re-installing Knoppix would be the first thing to try.

Step (5), when you do it with a hard-drive boot, is just a sanity check for (3) and (4). The cat command tells the system to dump a file to your screen (or somewhere else if you use, for example, the pipe). If the file is big you'd probably use less instead. But the ones in (5) and (6) are small.

When you're connected to the net, (5) will have a line for eth0 with non-zero numbers. If you wait a bit and enter the command again, the numbers will be bigger. A line with all zeros means the hardware was found, but the connection wasn't made. No line means no hardware found.

In step (6), substitue 2.4.27 or 2.6.9 for (kernel-version). If Linux found your internet hardware (controller), this file has its name and also the name of the device driver that Linux is using. An empty file means no hardware detected, but if it names the controller and not the driver, then you have a more interesting situation.

Well ... it's interesting if you're curious about why a kernel module gets loaded from the CD but not from the HD. But you probably aren't. In which case, try re-installing.

If you decide to re-install for whatever reason, and you still have the problem, then maybe your CD has a bizarre flaw right where it goes through the installation steps. A blip like that, that doesn't crash the whole process, would be truly astounding. But they say that bad CDs are the #1 cause of problems - whoever "they" is.

Let us know what you find, okay?

-- Ed