Test Route

This seems brain dead. I think the intent of 1597 was to say here
are some numbers you can go play with privately. Since they are
private they should never appear on the public Internet, anywhere,
ever. If any router on the public Internet sees a packet to (or
from) a 1597 network it can throw it in the bit bucket and forget it.

    As long as you say "can" rather than "must". Right now these sort of
    packets will follow the default route.