This feature is new in the Solaris Express 8/04 release.
IKE can now initiate IPsec security associations from behind a Network Address Translation (NAT) box. Only the ESP protocol over an IPv4 network is allowed. Additionally, IPsec security associations for traffic that traverses a NAT cannot be accelerated with the Solaris Crypto Accelerator 4000 board. IKE acceleration is unaffected.
For more information, see the ipseckey(1M) man page.