Prevention is always better than a complicated fix. Here are some best practices:
Older versions of PF separated NAT (Network Address Translation) and RDR (Redirection) into distinct rule blocks that had to precede filtering rules. Modern PF combines them. nat on ext_if from $localnet to any -> (ext_if) Use code with caution. Modern Correct Syntax: match out on ext_if from $localnet to any nat-to (ext_if) Use code with caution. 4. Table and Anchor Nesting Differences pf configuration incompatible with pf program version
The same issue can affect users on FreeBSD and other BSDs using binary updates. If a system upgrade is interrupted, or if only the kernel is updated via a source build but userland packages are left untouched, a mismatch occurs. FreeBSD users have reported these symptoms after an upgrade from 10.0-RELEASE to 10.1-RELEASE where the freebsd-update process failed to update all the components properly. In such cases, the pfctl binary ends up with a hash that does not match the expected hash for that release, while the kernel expects the newer version. Prevention is always better than a complicated fix
: You might have upgraded the user-land tools (like pfctl ) without rebooting to the new kernel, or vice-versa. nat on ext_if from $localnet to any ->
support that are absent or handled differently in the OpenBSD upstream. Final Thoughts