eth0 config probs (dhcp nature)

[Harry Kuhman]

ok i have an one cable internet connection

so far so good

i have a v old pc running knoppix 3.6 which works using this connection /shutdown/halt/reboot she will fire up and connect to the internet. she is also my server (she is a 386 with about 64 meg of mem and a 10gb hd!!!)

i want to upgrade to a faster pc so i have a 512 meg mem/120gb hd also with knoppix 3.6 on

the thing is once installed and rebooted i have to reconfigure eth0 each time to pick up the dhcp for the ipaddress (btw i have reformated the hd with various flavours of knoppix from 3.3 to 3.8.1 and non of them hold the settings for the eth0 i hae compaired /etc/network files between the 2 machines and there is no difference)

Now several factors rear their ugly head. You're talking about a hdd install of Knoppix? Then I would suggest that the best place for discussing it would have been the hdd install forum. Sure, there is some cross over, but if networking works fine from the CD but not from a hdd install (as is typical) then it's not a networking issue, it's a hdd install issue. And if networking doesn't work from the CD then lets not even bring in the hdd install, lets just get it working from the CD.

But the topic is started here, so lets see if we can resolve it. All home routers I've seen have a feature to let you change the router's MAC address, and the purpose seems to be to match a MAC address the ISP alread is seeing. This leads me to believe that maybe some cable companys do use the MAC address for determining what system to set up. There is no difference between the network files in the 2 systems, but there is a difference in the mac addresses of the 2 NIC cards. So my guess is that this could be the issue.

If you want to try an experiment and the 2 nics are on cards that can be swapped (rather than built into the MB or different bus structures), then get the old system working on the cable system, shut it down, swap nics, and bring te new system up on the cable. See if it now configures correctly. Then see if the old system "fails" in the same way the newer system did.

....to clarify only one pc is on at a time as i only have on connection to the internet (i have not even attempted to plug this in to my lan until i can sort this out)

You have a LAN? How do you manage to work putting one or the other computer on the canle modem but not even trying to connect the lan to it?

What is the central connection device of your LAN? That is, do you have a router, or is your LAN just built around hubs and or switches?

I've posted many many times before that I strongly believe that most Internet problems posted in these forums would simply vanish if people used simple inexpensive DSL/cable routers. These things, recently costing hundreds of bucks, are now frequently as low as $10 US or less after rebate (in some cases free). I didn' see any $10 ones this week, but I did see a name brand Linksys with wireless support for $15 in the ads this weekend and Best Buy has a high speed 802.11g Wireless and wired Dlink router and it includes a high speed 802.11g pcmcia card for $20 after rebate this week. Such a device will hook up to your ethernet based cable or DSL connection and let all systems share the connection. They form the central basis of a LAN. They take care of all dealings with the ISP for you and assign local IP addresses to all systems through DHCP. For Knoppix (and even windows) that means that getting on the Internet is as simple as booting your computer, you boot, you're on the network, no extra setup needed, even when running from the live CD (actually, from what I have seen in the forums, running from a HD install may add it's own problems). The router will also provide an important hardware filewall. And if it does turn out that your problem is a MAC address issue, the router can be set to show the same MAC address to the ISP and keep them happy (while your local netwirk, of course, sees a different MAC address). In any event you do a very simple setup on the router once and then all your knoppix systems will boot and run find, and all at the same time.

....as i have a smattering of network knowdge i find this very frustrating!!!

I suspect that you are about to get more network knowledge..