And RFC 7084 states in L-14 that IPv6 Router MUST send ICMPv6 Destination
Unreachable with code 5 for packets forwarded to it that use an address
from a prefix that has been invalidated.
Codes 5 and 6 are more informative subsets of code 1.
Signed-off-by: Andreas Herz <andi@geekosphere.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>