Howto ping hosts on LAN and Halt System

[Rasco]

I am looking for a script that can ping hosts on the LAN and WLAN and when there are no host left, then pfSense router can halt the system.
The reason is that my network 70% of the day doing nothing.

[esnakk]

@Rasco:

I am looking for a script that can ping hosts on the LAN and WLAN and when there are no host left, then pfSense router can halt the system.
The reason is that my network 70% of the day doing nothing.

Why not do it the other way around? Configure your router to use wake on lan (WOL) and if there IS traffic, it boots up and stays up. Sounds dangerous to allow a script to shut down the system. How ever a quick and dirty shell or perl script that checks the output of, for example tcpdump on an interface and a loop and a counter to check if nothing happened for X amount of minutes etc.

OT: If electricity cost is the issue, why not switch to less power hungry components such as Intel Atom or similar, the power consumption on these while idling is almost none and probably switches, UPS, etc consumes more power than the router itself during these times your network users are busy IRL?

Cheers
E