[COLUG] Gb ethernet up at only 100 Mb

[Brett Stauffer]

My CentOS 4.3 system's motherboard has a GB Ethernet interface onboard. 
The interface is properly detected, and an LED on my switch (a cheap
GigaFast 5 port) reports the link up at 1000 Mb/s.  ethtool reports the
interface up at only 100 Mb/s, yet being capable of 1000 Mb/s:

    [root at direwolf ~]# ethtool eth0 | grep 10
            Supported link modes:   10baseT/Half 10baseT/Full
                                    100baseT/Half 100baseT/Full
                                    1000baseT/Half 1000baseT/Full
            Speed: 100Mb/s

I've tried switching cables, with no change.  I have other systems
connected through this switch, which run at 1000 Mb/s just fine.

What am I missing here?  I appreciate any insight.


thanks,
--brett