This feature is new in the Solaris Express 2/04 release.
Solaris IP Filter is a host-based firewall that is based on the open source IP Filter. Solaris IP Filter provides packet filtering and network address translation (NAT), based on a user-configurable policy. Packet filtering rules are configurable in either a stateful or stateless manner. All configuration and management of Solaris IP Filter is performed through a command-line interface.