bizarre dhcp problem

buttholio · Posted: Mon Sep 30, 2002 7:14 pm Post subject: bizarre dhcp problem

Hi,
I'm a new Gentoo user, so please bear with me. To cut the long story short:

1) INSTALL: used UT2K3 install CD, went smoothly, dhcp during setup worked, all good, compiled my oh-so-fresh-and-clean kernel, etc
2) FIRST BOOT: dhcp refused to work. Failed during boot, when launched from the console, it just hangs there

The problem is the kernel. I arrived at this conclusion by copying the kernel image from the install CD to my boot partition, adding an entry for it in grub and booting off of it. With this kernel all is good, dhcp is happy, eth0 is brought up.

I would think the only kernel settings differences that would cause this would be the networking options. Now i've tried enabling almost everything under networking options and different combinations of them but the newly compiled kernel somehow makes dhcp not responding.

For the time being I'm using the install CD kernel to boot my fresh gentoo install so I can configure it further, so it's not a critical problem. It's just that I'm curious why the newly compiled kernel causes this: is there a problem with the kernel or am I missing something trivial here?

To save some possible answers:
- yes, I compiled my eth0 device driver into the new kernel; eth0 is present under the new kernel
- tried with and without io mapped sockets, no difference
- my eth0 card is dec tulip 21041

Thanks in advance

ZagiFlyer · Posted: Mon Sep 30, 2002 8:01 pm Post subject:

I know you've compiled the network card into your kernel, but have you examined the output of 'lsmod' when you've booted from the CD and everything works?

Just a start. That's what has solved a few of my own problems.
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buttholio · Posted: Mon Sep 30, 2002 8:43 pm Post subject:

Thanks for the reply. The CD image kernel has my card compiled into it, lsmod doesn't show anything and I didn't have to modprobe in order to get my eth0 to work. Same with my custom kernel: the card is present (dmesg + cat /proc shows it), it's just not initialized since dhcp times out.

pjp · Administrator Joined: 16 Apr 2002 Posts: 20583

To compare the differences between your .config and the CD's, you could try running grep -v "#" .config | grep CONFIG. Do the same on for the CD .config file and go over the differences.

This may not be the file you want, but might help in finding the correct one.
config-2.4.19-gentoo-r7?rev=1.1
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buttholio · Posted: Tue Oct 01, 2002 9:48 pm Post subject:

Thank you very much. The problem was the ethernet driver. Many hours of experiments and kernel rebuilding revealed that in order to get the DEC tulip eth0 driver working you gotta also include "DEChip generic support & some other crap". What was misleading was the fact that the driver was happily starting up during kernel boot but wasn't actually functioning (whether in-kernel or as a module). The other thingy made it tick.

ajaustin · n00b Joined: 18 Oct 2002 Posts: 38 Location: Surrey UK

I would like to add my tuppence-worth to this as I have just been through the same problem with a Digital DEC chip 21041 NIC. It worked fine with the installation CD kernel but did not work with the tulip.o driver which is shown in "make menuconfig" as "DECchip Tulip (dc21x4x) PCI support".

I expected it to work with the tulip.o driver as this was the one that several people said that they used, but it didn't.

It does work with the de4x5.o driver, which is "Generic DECchip & DIGITAL EtherWORKS PCI/EISA" in "make menuconfig".

My card is one that I found in my odd box and has the brand name Kingston model KNE40BT, if that makes any difference.