Comment 16 for bug 713385

I can also confirm this is a bug. We are using Cobbler to netboot systems (RedHat and Ubuntu). The RedHat systems have no problem using PXE or iPXE with multiple NICs. Ubuntu 16.04 *seems* to work with PXE, but fails during DHCP with iPXE chainloading.

I believe the issue is that the standard PXE process actually passes some network information to the bootloader so the DHCP process chooses the right interface to bring up, but this same information is getting dropped along the way during iPXE chainloading.

This wouldn't be an issue for us because we are actually assigning static IPs in the preseed file, however, the preseed file isn't available until AFTER the NIC is up to pull down the file (chick v. egg). It might be possible to pre-load all of the static network information in the kernel options and disable DHCP altogether, however, this seems a bit obtuse for a process which should be simple and lightweight in the first place.

I think the correct behavior for "interface=auto" is that it actually loops through the interfaces and tries to DHCP on each one until it gets a valid response.

In the meantime, since this bug is SUPER old, I can +1 verify that @spuzirev's workaround with "interface=${netX/mac}" in the kernel options works like a charm and avoids the "BOOTIF=<mac>" hardcoding.