Comment 12 for bug 505916

Reopening, because setting clientid in pxelinux.cfg/default is not an acceptable solution. The DHCP RFC states that the clientid should be unique on the local network, and not doing so causes serious problems with certain RFC-compliant dhcp servers.

The current udhcp package is ancient (>5 years old) and doesn't have the necessary "--clientid-none" switch .
The udhcp codebase has been moved to busybox. That newer udhcpc does have the --clientid-none switch (line 165 in http://git.busybox.net/busybox/tree/networking/udhcp/dhcpc.c?h=1_16_stable&id=53283adb24765a7afb4d6298661c3c1a8d6f5601)

So as soon as that new udhcp package lands in Ubuntu (https://bugs.launchpad.net/ubuntu/+source/udhcp/+bug/566845), we can drop --clientid completely and start using -C instead, which should be a proper solution to this bug report.