dnsmasq doesn't play well with OpenBSD
Try to pxeboot install OpenBSD, and was surprised to find I can not use dnsmasq. dnsmasq is the right thing to do this work, it is simple, it is compact, it has dhcp/dns/tftp integrated in one and is the perfect choice for pxe install, except for OpenBSD.
OpenBSD's pxeboot requires reverse arp, and check this out:
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2007q1/001185.html
Sigh!