Bug 5627

Most recent kernel where this bug did not occur: (probably 2.4.20 - I don't
remember)
Distribution: Fedora Core 4 (kernel from kernel.org)
Hardware Environment: P-IV 2.4 Ghz, 256 MB RAM, 40 GB IDE HDD
Software Environment: N/A
Problem Description:
Currently I am trying to establish a PXE boot environment for several machines
to boot Linux over the network. Today I compiled the kernel with the
CONFIG_IP_PNP and CONFIG_ROOT_NFS and tried to boot it remotely.
It boots, printing the following:
IP-Config: Got DHCP answer from 192.168.10.10, my address is 192.168.10.111
IP-Config: Complete:
device=eth0,addr=192.168.10.111,mask=255.255.255.0,gw=192.168.10.1,
host=student11,domain=c201,nis-domain=(none),
bootserver=192.168.10.10, rootserver=192.168.10.10,rootpath=

Kernel command line: root=/dev/nfs ip=dhcp

The infrastructure is as follows:
tftp & nfs Linux server (no isc-dhcpd installed) - address 192.168.10.10
DNS, Gateway AND DHCP server (FreeBSD) - 192.168.10.1

i.e. the kernel obtains all the network parameters correctly from 192.168.10.1,
but reports that the DHCP response has been received from 192.168.10.10.

This is all coded at lines 1156 and 1364-1373 of the file
/usr/src/linux/net/ipv4/ipconfig.c

If I had some more time, I would be glad to study ipconfig.c in detail and
probably fix this bug, but I need to get on with my A-Level studies.

Steps to reproduce:

1.Compile a kernel that is able to be booted remotely
2. Make one machine DHCP server (say, IP 10.1.1.1), and another machine -
tftp+nfs server (where the rootfs is mounted, and kernel is taken from - say,
10.1.1.2)
3. Try to boot the kernel - it reports that network configuration parameters
have been obtained using DHCP from 10.1.1.2, rather than from the real DHCP
server, 10.1.1.1, although in fact the settings are obtained from 10.1.1.1.