I can not disable the auto-negotiation (eth1) on my centos 6.2 via ethtool or /etc/sysconfig/network-scripts/ifcfg-eth1 the eth1 is a private network on a cheap gigabit-switch (under controll from a serverhoster). sometime the ethernet-card lost the "speed" and "duplex" information and change it to "unknown". i can only fix this with a network-restart (or ifup/ifdown). now i will disable the autonegotiation - but i does not work. thanks sebastian