10.22. Why do I get ``/dev/bpf0: device not configured"?

The Berkeley Packet Filter (bpf) driver needs to be enabled before running programs that utilize it. Add this to your kernel config file and build a new kernel:

	 pseudo-device bpfilter		# Berkeley Packet Filter
       

Secondly, after rebooting you will have to create the device node. This can be accomplished by a change to the /dev directory, followed by the execution of:

       # sh MAKEDEV bpf0
       

Please see the handbook's entry on device nodes for more information on creating devices.