I have a tool that I want to run in the %pre script of a kickstart install but it complains that the "network is not reachable". I can assign an IP address to eth0 while running in %pre and can access external addresses via unicast, but attempts to use broadcast messages fail.

Is there something I need to do to enable broadcast support while running in a %pre script?

Based on some testing and some searches, one potential issue is that broadcasts don't work if a default route isn't defined. That doesn't make sense to me. The dhclient program for example uses a broadcast protocol under the covers to obtain IP information, and the whole intent is it can be used when a system doesn't have any IP information, and that includes no default gateway defined. So the very fact that dhclient works within the environment where the %pre script runs means that I should be able to write my own tool (I'm using Python) to use a broadcast protocol.

Perhaps I need to resort to raw sockets?