options ICMP_BANDLIM
в нете по указанному вопросу ни чего не находил. Да ветвь фри 5.

Модератор: terminus
options ICMP_BANDLIM #Rate limit bad replies
This option enables ICMP error response bandwidth limiting. You typically want this option as it will help protect the machine from denial of service packet attacks.
Note: In FreeBSD 5.0, this feature is enabled by default and the ICMP_BANDLIM option is not required.