I needed to support PXE booting on my home network. I use OpenWRT as my main router and DHCP server and it took me a bit of searching how to configure the BOOTP next server to redirect local clients to my Arch TFTP/NFS server for booting, so I'm placing the configuration here to help others who might be looking to do the same thing.
It's worth noting that this isn't a guide on setting up PXE booting completely on an OpenWRT, you'll need another system that is running a configured TFTP server. I'll write up how I setup my Arch box as a TFTP server at a later date.
The configuration itself was very simple; You just need to add a couple lines
/etc/config/dhcp. You'll want to replace 10.0.0.45 with whatever your
local TFTP server is.
config boot linux option filename 'pxelinux.0' option serveraddress '10.0.0.45' option servername 'Arch-Pixie'
pxelinux.0 is from Syslinux, and the
servername has no
technical meaning, but it provides nice information to the clients. In this
case I've used the name of my Arch linux server that I'll be booting off of.
Hope this helps someone out. Cheers!