[CentOS] RTL8111/8168B always 100mbps

Tue Sep 27 14:11:10 UTC 2011
m.roth at 5-cent.us <m.roth at 5-cent.us>

John Doe wrote:
> From: "m.roth at 5-cent.us" <m.roth at 5-cent.us>
>> I was working on a similar problem (turned out to be our network
>> switch),
>> but *did* find that order of the ethtool command is significant: you
>> *MUST* have autoneg off as the first parameter; that is, try
>> # ethtool -s eth0  autoneg off speed 1000 duplex full advertise 0x020
> Tried that but I still get autoneg on... and 100Mbps.
> In fact, the only way to have autoneg really off seems to not include
> "speed 1000"...
> But if I do not put "speed 1000", nothing changes.
> And as soon as I put "speed 1000", autoneg is back on... even with
> "autoneg off" in front...

Dumb question: have you tried plugging any other system with a 1Gb NIC
into that port on the switch?