There were important bugs in versions 0.4.0 /0.4.1 impacting the network booting via pxe. The DNS and default-router (gateway) options of the DHCP server were ignored by the PXE client. After the kernel is downloaded via TFTP and it finishes booting, the initramfs environment downloads the sysrcd.dat file that contains the whole system files.

You may need the default-router parameter if you want to download the sysrcd.dat file from an HTTP server located on another subnet. And you may need the DNS name resolution if you give an URL with names for the sysrcd.dat. These two network options have been fixed in SystemRescueCd-0.4.2-beta11. It means if you configure the DHCP server options with valid DNS and GATEWAY ip addresses, they should work from the initramfs environment now.

Here is the topic in the forums related to the DNS bug. If you still have networking issues related to the PXE, please post in the forum about network booting via pxe.

You should also use the following new boot options with 0.4.2-beta11 and newer:

• option rootpass=xxx sets the root password of the live system to xxx
• option ethx=ipaddr sets the a static IP address of all the ethernet interfaces found on the system
• option gateway=ipaddr sets the default route by hand
• option dns=ipaddr sets the DNS name server by hand

For instance, you can boot with the following boot image and options:
rescuecd ethx=192.168.1.1 dns=212.27.32.5 gateway=192.168.1.254