Linux Kernel NetworkingChapter 9: Netfilter and FirewallsChapter 9: Netfilter and Firewalls This chapter contains 10 sections. Click the links below to read: Netfilter Frameworks Netfilter Hooks Connection Tracking Initialization Connection Tracking Entries Connection Tracking Helpers and Expectations IPTables Network Address Translation (NAT) NAT Hook Callbacks and Connection Tracking Hook Callbacks NAT Hook Callbacks Quick Reference