Introduction to IP Filter

The IP Filter feature of Oracle Solaris replaces the SunScreen firewall in the OS. Like the SunScreen firewall, IP Filter provides stateful packet filtering and network address translation (NAT). IP Filter also includes stateless packet filtering and the ability to create and manage address pools.

Packet filtering provides basic protection against network-based attacks. IP Filter can filter by IP address, port, protocol, network interface, and traffic direction. IP Filter can also filter by an individual source IP address, a destination IP address, by a range of IP addresses, or by address pools.

IP Filter is derived from open source IP Filter software. To view license terms, attribution, and copyright statements for open source IP Filter, the default path is /usr/lib/ipf/IPFILTER.LICENCE. If Oracle Solaris has been installed anywhere other than the default, modify the given path to access the file at the installed location.

Information Sources for Open Source IP Filter

The home page for the open source IP Filter software by Darren Reed is found at http://coombs.anu.edu.au/~avalon/ip-filter.html. This site includes information for open source IP Filter, including a link to a tutorial entitled “IP Filter Based Firewalls HOWTO” (Brendan Conoboy and Erik Fichtner, 2002). This tutorial provides step-by-step instructions for building firewalls in a BSD UNIX environment. Although written for a BSD UNIX environment, the tutorial is also relevant for the configuration of IP Filter.