There is however another way to activate the firewall. This is to use a special daemon program to monitor all network interfaces in the system. Whenever an interface is changed the firewall script is executed. If the interface is the internet interface, the firewall will be activated. This also takes care of a possibly change of ip addresses on this interface.
The dameon is fast and will be able do the check many times every second.
The daemon is started by the Act/Changes button in Linuxconf or by running
It can also be started directly from a rc-script: