Ipfw fwd with route(8) RTF_BLACKHOLE and fast forwarding on FreeBSD 11

[Eugene Grosbein]

> As temporary workaround, you still can disable fast forwarding path:
> 
> - make sure you use GENERIC kernel or your custom kernel has "options IPSEC_SUPPORT" like GENERIC has;
> - load ipsec kernel module by means of /boot/loader.conf or /etc/rc.conf;
> - add dummy security policy:
> 
> printf "flush;\nspdflush;\n\nspdadd 100.64.0.1/32 100.64.0.2/32 esp -P out none;\n" > /etc/ipsec.conf

- finally, do: echo ipsec_enable=YES >> /etc/rc.conf

> It does nothing but prevents a kernel from using fast forwarding path for 11.2