This feature is new in the Software Express pilot program. This feature is included in the Solaris 10 3/05 release.
The new router option of ifconfig allows you to configure IP packet forwarding on individual interfaces. ifconfig router and ifconfig -router enable or disable IP packet forwarding, respectively, for both IPv4 and IPv6 interfaces. The router option sets the IFF_ROUTER interface flag.
These new options replace the ndd variables interface-name:ip_forwarding and interface-name:ip6_forwarding for configuring IP packet forwarding on individual interfaces. Though now obsolete, the ndd variables remain in this Solaris release for backward compatibility. You can still use ip_forwarding and ip6_forwarding without the interface-name prefix to configure IP forwarding for all interfaces on a system.