| This creates an LED-trigger that can then be attached to system indicator |
| lights, to blink or illuminate them when certain packets pass through the |
| system. One example might be to light up an LED for a few minutes every time |
| an SSH connection is made to the local machine. The following options control |
| the trigger behavior: |
| .TP |
| \fB\-\-led\-trigger\-id\fP \fIname\fP |
| This is the name given to the LED trigger. The actual name of the trigger |
| will be prefixed with "netfilter-". |
| .TP |
| \fB\-\-led-delay\fP \fIms\fP |
| This indicates how long (in milliseconds) the LED should be left illuminated |
| when a packet arrives before being switched off again. The default is 0 |
| (blink as fast as possible.) The special value \fIinf\fP can be given to |
| leave the LED on permanently once activated. (In this case the trigger will |
| need to be manually detached and reattached to the LED device to switch it |
| off again.) |
| .TP |
| \fB\-\-led\-always\-blink\fP |
| Always make the LED blink on packet arrival, even if the LED is already on. |
| This allows notification of new packets even with long delay values (which |
| otherwise would result in a silent prolonging of the delay time.) |
| .TP |
| Example: |
| .TP |
| Create an LED trigger for incoming SSH traffic: |
| iptables \-A INPUT \-p tcp \-\-dport 22 \-j LED \-\-led\-trigger\-id ssh |
| .TP |
| Then attach the new trigger to an LED: |
| echo netfilter\-ssh >/sys/class/leds/\fIledname\fP/trigger |