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I am trying to monitor for network failures on a machine, and one portion of that is to monitor interfaces that are intended to be active also be "RUNNING".

An Ethernet port, such as eth0, will say "RUNNING" if it is physically connected to another device.

The problem lies in the bonded interfaces, such as bond0. If all of the ethernet devices are disconnected, it still says that it is running, and it is still pingable. Is this by design, or is my system setup incorrectly? Does the miimon option have something to do with this?


I found a possible issue, thanks to Gregor. When I ran cat /proc/net/bonding/bond0, it gave me this (notice MII Polling Interval):

Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth7
MII Status: up
Link Failure Count: 0

But in my /etc/modprobe.conf, I set it up like this:

alias bond0 bonding
options bond0 -o bond0 mode=0 miimon=100

So, evidently, the miimon setting is not working correctly.

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up vote 1 down vote accepted

Your script could scan /proc/net/bonding/bondX for some status information. - Greg

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Ah, found a possible problem. I will edit the main post with updated info. – bradlis7 Apr 1 '10 at 21:40
Well, what do you know, rebooting fixed it. I don't think I did anything to change it, but maybe I did. – bradlis7 Apr 1 '10 at 22:08

Have you looked at ethtool or mii-tool? That's typically how I determine link status without physically inspecting the server in Linux.

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Well, that's a better way to do it, but it has the same issue. It says the link is up, but no slaved devices are connected. See my edit above. – bradlis7 Apr 1 '10 at 21:44

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