Ethernet cable check

[Roman Maeder]

Matthew Miller wrote:
> On Tue, Jan 18, 2005 at 12:58:39PM +0100, Roman Maeder wrote:
>> init.d/network greps for "ONBOOT=no" and if it finds it, skips the
>> interface. My new version no longer contains this substring, so it seems
>> to work, but I wonder whether there isn't a more standard solution.
> 
> If I remember right, there used to be some trickery in the init scripts to
> do just this, but it turns out to not be reliable with all network cards /
> drivers, causing worse problems than it solves.
> 

and I wrote:
> is there an official way to check for the presence of an ethernet cable
> for  an interface? ...

after posting my question I stumbled on the check_link_down() function in
/etc/sysconfig/network-scripts/network-functions. It is used only when
configuring wireless interfaces, but tries to use mii-tool and ethtool to
check whether a link is up. I guess it makes sense to not use it and always
configure wired interface on a server, but on a laptop the network cable
can be unplugged in purpose and I'd like it to react accordingly. I don't
like hacking on the scripts in network-scripts/, and there seem to be some
hooks provided for extensions.

Roman