There are a number of ways to enable configuration changes in Vuurmuur.
- restart vuurmuur, by running /etc/init.d/vuurmuur restart or a similar command that kills (with INT or TERM signals) the vuurmuur processes and starts them again.
- send a signal to vuurmuur and vuurmuur_log. This must be the HUP signal.
- choose 'Apply changes' from the main menu in vuurmuur_conf, or press F11 in the main menu.
- for vuurmuur_script the option --apply is available, so it applies the changes the same way vuurmuur_conf does
If applying the changes failed take a look a the error.log.
If Vuurmuur somehow created a iptables ruleset that iptables refused to load, there will be two files in /tmp/ to inspect. The first is /tmp/vuurmuur-load-result-XXXXXX (the X's are random characters) which contains the output of the iptables-restore command.
The second will be called /tmp/vuurmuur-XXXXXX.failed. This is the failed ruleset itself. Vuurmuur loads this file with the following command:
iptables-restore --counters --noflush < /tmp/vuurmuur-XXXXXX
You can try to run it manually for debugging. If inspecting the files doesn't bring a solution, please consider contacting the developers for support.