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This is the BSDA Study Guide Book written via a wiki collaboration. This is a work in progress. You may contribute to or discuss this specific page at http://bsdwiki.reedmedia.net/wiki/Recognize_BSD_firewalls_and_rulesets.html. Recognize BSD firewalls and rulesets Concept Each BSD comes with at least one built-in firewall. Recognize which firewalls are available on each BSD and which commands are used to view each firewall's ruleset. Introduction Each BSD comes with at least one built-in firewall. NetBSD provides IP Filter (IPF) and PF (from OpenBSD). FreeBSD has its own IPFW, IP Filter, and PF. OpenBSD includes is own PF. And DragonFly has IPFW, IP Filter, and PF. IP Filter (IPF) IP Filter is a featureful, stateful, advanced packet filter, address translation (NAT)), and proxy software developed by Darren Reed. It is available for Solaris, DragonFly, FreeBSD, NetBSD, HP-UX, and some other operating systems. TODO: show one or two examples how to detect if it is available and if it is enabled TODO: point to default startup script for enabling (and mention issues with that) TODO: point to location of default configurations TODO: point to included documentation and examples TODO: show how to view loaded ruleset TODO: show a very brief example (three rules/lines) and use same functionality for all three firewalls here IPFW IPFW is an IP firewall and traffic shaper developed by FreeBSD. It is also available for DragonFly. (A derivative of IPFW is available on Mac OS X.) Network address translation is handled in the userland by the natd daemon. The ipfw tool can be used to control and configure the firewall and also to configure the dummynet system which is used for bandwidth limits, queueing, and simulating losses and delays. TODO: show one or two examples how to detect if it is available and if it is enabled TODO: point to default startup script for enabling (and mention issues with that) TODO: point to location of default configurations TODO: point to included documentation and examples TODO: show how to view loaded ruleset TODO: show a very brief example (three rules/lines) and use same functionality for all three firewalls here PF pf - packet filter first appeared in OpenBSD 3.0, since then it has been imported into FreeBSD, NetBSD and DragonFlyBSD. The packet filtering takes place in the kernel. A pseudo device /dev/pf allows userland processes to control the packet filter. Communication with the pf is usally achieved using pfctl. The default configuaration is stored in pf.conf. TODO: show one or two examples how to detect if it is available and if it is enabled TODO: point to default startup script for enabling (and mention issues with that) TODO: point to location of default configurations TODO: point to included documentation and examples TODO: show how to view loaded ruleset pfctl -sr show rules TODO: show a very brief example (three rules/lines) and use same functionality for all three firewalls here Practice Exercises More information ipfw(8), ipf(8), ipfstat(8), pf(4), pfctl(8) and firewall(7)