shutting down an interface when another interface goes down

deadheadblues · 11-07-2014, 04:54 PM

Hi. I want to be able to shutdown eth2 if eth1 were to lose its network connectivity. This could be due to a shutting down of the upstream switch or unplugged cable or something else.

Is it possible to do this? What are some options?

Thanks,

Ser Olmy · 11-07-2014, 07:56 PM

If the loss of connectivity generates an event of some kind, you could probably create a udev rule to tie that event to any action you like.

sdblanchet · 11-17-2014, 05:48 PM

The question is
How fast do you need to shutdown the other interface ?

A command like this in a script from a cron job go do it but you must not be in a hurry
RES=`ping -c 1 your_running_interface | grep '1 received' | awk '{print $4" "$5}'`
if [ "x$RES" == "x" ]; then
ifdown you_interface_to_shutdown
fi

I would be careful about the consequences from shutting down the other interface.