"LED" target support

modulename: xt_LED.ko

configname: CONFIG_NETFILTER_XT_TARGET_LED

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>Core Netfilter Configuration
└─>"LED" target support
In linux kernel since version 2.6.30 (release Date: 2009-06-09)  
This option adds a `LED' target, which allows you to blink LEDs in
response to particular packets passing through your machine.

This can be used to turn a spare LED into a network activity LED,
which only flashes in response to FTP transfers, for example. Or
you could have an LED which lights up for a minute or two every time
somebody connects to your machine via SSH.

You will need support for the "led" class to make this work.

To create an LED trigger for incoming SSH traffic:
iptables -A INPUT -p tcp --dport 22 -j LED --led-trigger-id ssh --led-delay 1000

Then attach the new trigger to an LED on your system:
echo netfilter-ssh > /sys/class/leds/<ledname>/trigger

For more information on the LEDs available on your system, see
Documentation/leds/leds-class.rst

source code: