Firewall Rule Processing Order

From PFSenseDocs
Jump to: navigation, search


Rules in pfSense are processed in a specific order. Understanding this order is especially important when crafting more complicated sets of rules and when troubleshooting. This document is intended to give a general idea of how rules are processed. It can be much more complicated, especially when floating rules are involved and out direction rules are used. See The pfSense Book for more in-depth information.

Short Version

Rules are always processed from the top of a list down, first match wins (except for floating rules without quick set, see the next section).

The tl;dr version of user-defined rule processing is:

  • Rules defined on the floating tab are processed first
  • Rules defined on interface group tabs (Including OpenVPN) are processed
  • Rules defined on interface tabs (WAN, LAN, OPTx, etc) are processed last

Longer Version

More accurately, the following order (still simplified) is found in the ruleset (Check /tmp/rules.debug):

  • Outbound NAT rules
  • Inbound NAT rules such as Port Forwards (including rdr pass and UPnP)
  • NAT rules for the Load Balancing daemon (relayd)
  • Rules dynamically received from RADIUS for OpenVPN and IPsec clients
  • Internal automatic rules (pass and block for various items like lockout, snort, DHCP, etc.)
  • User-defined rules:
    • Rules defined on the floating tab
    • Rules defined on interface group tabs (Including OpenVPN)
    • Rules defined on interface tabs (WAN, LAN, OPTx, etc)
  • Automatic VPN rules

Floating Rules notes

Floating rules without quick set process in a "last match wins" way instead of "first match wins" So if a floating rule is set without quick and it matches a packet, then a later rule also matches, the later rule will be used. This is the opposite of the other tab rules (groups, interfaces) and rules with quick set which stop processing as soon as a match is made. See What are Floating Rules for more details on how Floating Rules operate.