What is IPFilter? Very simply, a package for permitting (or passing) and denying IP packets based on a range of criteria. It can also provide Network Address Translation (NAT) services, if desired. The IPFilter web site has more details. . . .
What is IPFilter? Very simply, a package for permitting (or passing) and denying IP packets based on a range of criteria. It can also provide Network Address Translation (NAT) services, if desired. The IPFilter web site has more details.

The available rules range from quite simple -- for example, deny all traffic on any interface; to relatively complex -- pass and log all ICMP traffic of type ICMP-QUERY from the 199.232.41.24/29 subnet on interface fxp0. Each rule is one-way only, meaning you can block inbound HTTP requests without disrupting outbound requests. When bridging two cards together, OpenBSD's bridge device only checks incoming filter rules. Bidirectional rules are easily created by setting the inbound rules on the other NIC.

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