1*a71a9546SAutomerger Merge WorkerThis creates an LED-trigger that can then be attached to system indicator 2*a71a9546SAutomerger Merge Workerlights, to blink or illuminate them when certain packets pass through the 3*a71a9546SAutomerger Merge Workersystem. One example might be to light up an LED for a few minutes every time 4*a71a9546SAutomerger Merge Workeran SSH connection is made to the local machine. The following options control 5*a71a9546SAutomerger Merge Workerthe trigger behavior: 6*a71a9546SAutomerger Merge Worker.TP 7*a71a9546SAutomerger Merge Worker\fB\-\-led\-trigger\-id\fP \fIname\fP 8*a71a9546SAutomerger Merge WorkerThis is the name given to the LED trigger. The actual name of the trigger 9*a71a9546SAutomerger Merge Workerwill be prefixed with "netfilter-". 10*a71a9546SAutomerger Merge Worker.TP 11*a71a9546SAutomerger Merge Worker\fB\-\-led-delay\fP \fIms\fP 12*a71a9546SAutomerger Merge WorkerThis indicates how long (in milliseconds) the LED should be left illuminated 13*a71a9546SAutomerger Merge Workerwhen a packet arrives before being switched off again. The default is 0 14*a71a9546SAutomerger Merge Worker(blink as fast as possible.) The special value \fIinf\fP can be given to 15*a71a9546SAutomerger Merge Workerleave the LED on permanently once activated. (In this case the trigger will 16*a71a9546SAutomerger Merge Workerneed to be manually detached and reattached to the LED device to switch it 17*a71a9546SAutomerger Merge Workeroff again.) 18*a71a9546SAutomerger Merge Worker.TP 19*a71a9546SAutomerger Merge Worker\fB\-\-led\-always\-blink\fP 20*a71a9546SAutomerger Merge WorkerAlways make the LED blink on packet arrival, even if the LED is already on. 21*a71a9546SAutomerger Merge WorkerThis allows notification of new packets even with long delay values (which 22*a71a9546SAutomerger Merge Workerotherwise would result in a silent prolonging of the delay time.) 23*a71a9546SAutomerger Merge Worker.TP 24*a71a9546SAutomerger Merge WorkerExample: 25*a71a9546SAutomerger Merge Worker.TP 26*a71a9546SAutomerger Merge WorkerCreate an LED trigger for incoming SSH traffic: 27*a71a9546SAutomerger Merge Workeriptables \-A INPUT \-p tcp \-\-dport 22 \-j LED \-\-led\-trigger\-id ssh 28*a71a9546SAutomerger Merge Worker.TP 29*a71a9546SAutomerger Merge WorkerThen attach the new trigger to an LED: 30*a71a9546SAutomerger Merge Workerecho netfilter\-ssh >/sys/class/leds/\fIledname\fP/trigger 31