TRY THIS Raspberry Pi does not come up after network reset

[kyle95wm]

So, to make this a long story short, whenever I reboot my home's internet connection, my Raspberry Pi 2B doesn't seem to re-connect to the LAN. I wrote a script that's SUPPOSED to run every 5 minutes, which will ping an outside address three times. If these pings fail, the network interface is supposed to restart. I did an extended test today, and it was unable to deliver on what I expected. The only way to get the PBX back up and running was to power-cycle the Pi, which in itself is terrible for the SD card. Can anyone shed some light on why this is happening?

So, in short:

Expected behaviour: If the Raspberry Pi network is down, restart the interface
Actual behaviour: When the Raspberry Pi network is down, it never comes back up without a power-cycle.

 

[wardmundy]

How are you connecting to the LAN? Hard-wired or WiFi.
What command(s) are you using restart the LAN?

 

[kyle95wm]

How are you connecting to the LAN? Hard-wired or WiFi.

Ethernet. The Pi 2B has no built-in wifi

What command(s) are you using restart the LAN?

I'm so glad you asked! Here's the script that is SUPPOSED to run every 5 minutes:

#!/bin/bash

# This script will check to see if the host can ping the router.
# If the ping fails, shut down, then bring back up the interface designated as eth0

if ! /bin/ping 192.168.101.100 -c4 ; then
    # We first shut down eth0
    # After eth0 is shut down, we forcefully bring it back up
    /sbin/ifdown eth0 && /sbin/ifup --force eth0
else
    # We do noting if the network is okay
    /bin/echo "PBX is OK"
fi

Even changing the router to an outside address (such as 1.1.1.1) has no effect on fixing the downed network.

 

[wardmundy]

https://www.raspberrypi.org/forums/viewtopic.php?t=75137