[COLUG] Gb ethernet up at only 100 Mb

[Bill Baker]

On Tue, 2006-12-19 at 21:11 -0500, Brett Stauffer wrote:
> 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

Just to check the obvious, you are using cat6 cable and not cat5, right?