Hi Arran,
I have read the page you refer, and you say FreeRadius has no idea about the dropped packets. Would it be possible, or interesting to modify FreeRadius to give directly stats also like for instance named provides an interface for retrieving statistics?
How about performance of this particular solution of sniffing traffic? I wonder how much load? Granted, RADIUS traffic volume is particularly low, however, in linux, the packets have to be copied to userland to libpcap to use them, contrary to for example, FreeBSD. (Note: There is the PF_RING patch. I havent tested it out)
Note: Dont take the comments personally, it is just in the past I have always favoured solutions that were an alternative to sniffing traffic.
Regards,
Rui