Pf Configuration Incompatible With Pf Program Version Access

(where 1400000 indicates FreeBSD 14.0)

If you are maintaining a server and receive the error when trying to load or reload your Packet Filter (PF) rules, it means the structure of your rules file ( /etc/pf.conf ) does not match the syntax or features expected by the running version of the pfctl utility.

If you are in a raw environment and suspect a syntax error in pf.conf :

Understanding why this happens is the first step toward a stable network configuration. Usually, this occurs after a system upgrade where the userland utilities (the pfctl command) have been updated, but the kernel hasn't been rebooted to load the matching PF module. Conversely, it can happen if you are manually compiling a newer version of the PF tools while running an older kernel. Because PF relies on specific data structures to pass information between the command line and the kernel, even a tiny change in the code can break the communication bridge, leading to this compatibility error. pf configuration incompatible with pf program version

If you encounter this error inside a FreeBSD jail, the jail's userland binaries (including pfctl ) are likely newer or older than the host system's kernel.

Fixing the "PF Configuration Incompatible with PF Program Version" Error

pfctl -n -vvf /etc/pf.conf

If you are running a modern version of FreeBSD (12.x or newer), you should use the security/pf port. PF is a part of the base system, and installing this port can introduce version conflicts. Verify with:

Before changing any settings, locate the precise rule or keyword causing the incompatibility. Use the pfctl rule test command to validate the configuration file without applying it to the live network: sudo pfctl -nf /etc/pf.conf Use code with caution.

Different versions of PF handle specific features differently. Look out for these common historical syntax changes that frequently trigger compatibility errors: (where 1400000 indicates FreeBSD 14

sysctl kern.version

If you'd like to dive deeper into the technical side, let me know: What (macOS, FreeBSD, etc.) are you on? Did this happen after an update or a new installation ?