The packet filtering hooks interfaces help develop value added network solutions at the kernel level such as security (packet filtering and firewall) solutions and network address translation (NAT) solutions.
The packet filtering hooks interfaces provide the following capabilities:
Notification each time a packet appears at one of the hook points
Notification each time a new instance of IP is created to support a new zone booting that requires an exclusive instance of IP
Kernel access to other basic network interface information such as interface names and addresses
Interception of packets on the loopback interface
Loopback packet interception also provides access to packets as they move between zones that are using a shared instance of IP. This is the default model.