sysctl kern.version You are looking for discrepancies between the -k (kernel) and -u (userland). If they differ, you have found the culprit. Many systems have multiple pfctl binaries. Use which and version checks:
If you are a network administrator, security engineer, or FreeBSD enthusiast, encountering the error message "pf configuration incompatible with pf program version" can be a frustrating roadblock. This error typically appears when you attempt to load or manipulate a Packet Filter (pf) firewall ruleset, only to have the system reject your configuration.
pfctl: /etc/pf.conf: line 1: pf configuration incompatible with pf program version kernel: pf: DIOCXRULES: Inappropriate ioctl for device The administrator ran pfctl -V (showing version 1.9) and sysctl net.pf.version (showing version 1.8). After completing the userland upgrade and removing /var/db/pf.conf.db , the issue was resolved. Q: Can I ignore this error? A: No. PF will not start, leaving your system without a firewall. This is a critical security risk. pf configuration incompatible with pf program version
freebsd-version -kru | uniq Or for OpenBSD:
which pfctl pfctl -V Compare this with the kernel module version: sysctl kern
A: Use pfctl -V | grep version and sysctl net.pf.version . Conclusion The "pf configuration incompatible with pf program version" error is a classic symptom of a fractured system where the firewall kernel module and the management tools have drifted apart. While alarming, it is straightforward to diagnose and resolve.
By methodically checking version consistency, removing stale binary ruleset files, and ensuring complete system updates, you can restore your PF firewall to full functionality in minutes. Always remember: in the BSD world, a unified system is a stable system. Keep your userland and kernel in lockstep, and PF will protect your perimeter without complaint. If you continue to experience issues after following this guide, consult the official FreeBSD PF documentation or your specific BSD distribution’s mailing list. Always back up your /etc/pf.conf before making significant changes. Use which and version checks: If you are
A: Yes, if you use the pf kernel module on Linux (e.g., via Gentoo or pfSense's underlying FreeBSD heritage). The same principle applies.