On 2017-09-20 15:06, Ondrej Zajicek wrote:
If Linux and BSD kernels does accept such routes, than it is a strong reason to support that in BIRD, even if only for purpose of defining blackhole static route.
I could not say about BSD, but in Linux this is definitely possible (I have tried it - just to make sure).
So it seems strange to me that FIBs like Linux kernel does handle it regularly (never tried that), but perhaps they expect that now it will never be reassigned.
Well, the reason is (probably) that Linux gives you a lot of freedom and it is up to you how to do things - apart from few things nothing is hardcoded and nearly everything is tunable (it even allows you to break some RFCs). This is good as there are some cases when (re)compilation is not possible nor feasible (ROM-based embedded systems, for instance), and sometimes you have to deal with systems that are not under your control. I would simply include a (run-time) configuration switch to enforce some rules or to avoid them. Not a high priority task, of course, but it might make sense some day... But at the very least, the message itself should be a bit more informative :) Best regards, Alexander.