Netfilter

您可以在Wikipedia上了解到此条目的英文信息 Netfilter Thanks, Wikipedia.

netfilter.org is home to the software of the packet filtering framework inside the Linux 2.4.x and 2.6.x kernel series.

netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack.

iptables is a generic table structure for the definition of rulesets. Each rule within an IP table consists of a number of classifiers (iptables matches) and one connected action (iptables target).

netfilter, ip_tables, connection tracking (ip_conntrack, nf_conntrack) and the NAT subsystem together build the major parts of the framework.

Main Features

• stateless packet filtering (IPv4 and IPv6)
• stateful packet filtering (IPv4 and IPv6)
• all kinds of network address and port translation, e.g. NAT/NAPT (IPv4 only)
• flexible and extensible infrastructure
• multiple layers of API's for 3rd party extensions
• large number of plugins/modules kept in 'patch-o-matic' repository

Links

• http://netfilter.org/