There is one important thing I forgot to mention. In isakmpd deleting an IPsec SA also means deleting the appropriate IPsec policy in almost any case. Take a look at pf_key_v2_delete_spi() in pf_key_v2.c. It calls pf_key_v2_disable_sa(), the policy eraser ;-), if the SA was not acquired through the kernel: if (!(sa->flags & SA_FLAG_REPLACED) && !(sa->flags & SA_FLAG_ONDEMAND)) pf_key_v2_disable_sa (sa, incoming); Now imagine an IPsec tunnel between two security gateways running isakmpd. Both gateways are attacked, IPsec SAs and policies get removed, ... Thomas Walpuski