device connected

Is there a way in say the /proc filesystem to tell if the ethernet media is
actually connected or not? I understand how to tell if the device is there
or no.

In comp.os.linux.networking Michael Lodman
<jlodman@rainbow-networks.com> wrote:
> Is there a way in say the /proc filesystem to tell if the ethernet
> media is actually connected or not? I understand how to tell if the
> device is there or no.

You can use mii-tool and grep to prevent network services starting (dhcp
on a laptop is a pain on boot otherwise).

mii-tool eth0 | grep -q 'link ok' && dhclient

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Cameron Kerr
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Hi Michael,
> Is there a way in say the /proc filesystem to tell if the ethernet media is
> actually connected or not? I understand how to tell if the device is there
> or no.
Whether or not a cable is connected is information available from the ethernet card's
MII PHY. Depending on the card, this info is available to the linux driver, and you
can usually see it reported in the kernel logs. I have never seen any ethernet
driver implement it under a /proc entry, although it's not impossible.
There are also some user-space tools you may find of interest: mii-diag, mii-tool and
eth-tool, which talk to the mii via ioctls to the ethernet driver.

regards,

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