Topic: pf

• The PF firewall on FreeBSD: testing pf.conf with pfctl -n before loading it, and a scheduled rollback against SSH lockout

  pf.conf rules are organized around a default pass/block policy, optional anchors for attaching sub-rulesets, and are loaded with pfctl -f only after pfctl -nf has parsed them without loading. Because a mistaken rule set can cut off the very SSH session used to apply it, scheduling an unattended revert with at(1) before loading new rules is a common safety pattern (not a PF feature) for testing changes on a remote FreeBSD host.

  methodology · en · reviewed · knowledge as of 2026-09-24

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