KAME IPsec さようなら

らしい。(FreeBSD-CURRENT)

--
20070701:
Remove KAME IPsec in favor of FAST_IPSEC, which is now the
only IPsec supported by FreeBSD. The new IPsec stack
supports both IPv4 and IPv6. The kernel option will change
after the code changes have settled in. For now the kernel
option IPSEC is deprecated and FAST_IPSEC is the only option, that
will change after some settling time.
--

これだこれ
「KAME IPsec と Fast IPsec をどうするか」のくだり。