In this tutorial we will show you how to view your speed/duplexing setting and also changing your duplexing/speed settings

1. To view you interface settings, run this.."ethtool eth0"
   

   
   Settings for eth0:
           Supported ports: [ TP MII ]
           Supported link modes:   10baseT/Half 10baseT/Full
                                   100baseT/Half 100baseT/Full
           Supports auto-negotiation: Yes
           Advertised link modes:  10baseT/Half 10baseT/Full
                                   100baseT/Half 100baseT/Full
           Advertised auto-negotiation: Yes
           Speed: 100Mb/s
           Duplex: Full
           Port: MII
           PHYAD: 1
           Transceiver: internal
           Auto-negotiation: on
           Supports Wake-on: g
           Wake-on: g
           Current message level: 0x00000007 (7)
           Link detected: yes
     

    

   • To change your settings for eth0 you will have to do this...
     "ethtool -s eth1 speed 100 duplex full autoneg off"
   • REDHATTo make these changes permanently you will have to append this ETHTOOL_OPTS="speed 100 duplex full autoneg off"to the /etc/sysconfig/network-scripts/ifcfg-eth0 file
     
     

     
     DEVICE=eth0
     BROADCAST=192.168.101.255
     BOOTPROTO=static
     HWADDR=00:E0:81:24:CQ:82
     IPADDR=192.168.101.5
     NETMASK=255.255.255.0
     NETWORK=192.168.101.0
     ONBOOT=yes
     TYPE=Ethernet
     ETHTOOL_OPTS="speed 100 duplex full autoneg off"