How to detect ethernet connection

[Derek Broughton]

How, on a Kubuntu system, can one reliably tell if _any_ ethernet connection
exists?

leafnode (a minimal NNTP server) checks "ifplugstatus" (I'm not sure if it
does that stock, or if I added it):
 ifplugstatus | grep -e "eth.: link" >/dev/null  && fetchnews

This is functional, but requires me to have a daemon installed that I
otherwise have no use for (though this exercise has at least shown me that
my connections are no longer numbered the way I always thought they were -
eth0 is now eth1 and vice versa).

hal has apparently not got the right information - kde-hal-device-manager
tells me that net.interface_up is false for both interfaces.
-- 
derek