The Current System
input filtering and redirect to local ports
forward filtering and masquerading
- Can register a set of three hooks.
- Hooks can return FW_BLOCK, FW_ACCEPT, FW_REJECT, FW_REDIRECT,
FW_MASQUERADE or FW_SKIP.
- The next hook on that hook point only called if FW_SKIP returned.
- Hooks get ordered by numerical "preference".