使用ethtool工具来查看网卡是否工作

描述：
Ethtool是用于查询及设置网卡参数的命令。
概要：
ethtool ethX      //查询ethX网口基本设置
ethtool –h        //显示ethtool的命令帮助(help)
ethtool –i ethX    //查询ethX网口的相关信息 
ethtool –d ethX    //查询ethX网口注册性信息
ethtool –r ethX    //重置ethX网口到自适应模式
ethtool –S ethX    //查询ethX网口收发包统计
ethtool –s ethX [speed 10|100|1000]         //设置网口速率10/100/1000M
[duplex half|full]           //设置网口半/全双工
[autoneg on|off]            //设置网口是否自协商
[port tp|aui|bnc|mii]         //设置网口类型
[phyad N]                 
[xcvr internal|exteral]
[wol p|u|m|b|a|g|s|d...]
[sopass xx:yy:zz:aa:bb:cc]
[msglvl N]   

举例：

[root@dg1 ~]# ethtool eth0
Settings for eth0:
    Supported ports: [ TP ]
    Supported link modes:   1000baseT/Full 
                            10000baseT/Full 
    Supported pause frame use: No
    Supports auto-negotiation: No
    Advertised link modes:  Not reported
    Advertised pause frame use: No
    Advertised auto-negotiation: No
    Speed: 10000Mb/s
    Duplex: Full
    Port: Twisted Pair
    PHYAD: 0
    Transceiver: internal
    Auto-negotiation: off
    MDI-X: Unknown
    Supports Wake-on: uag
    Wake-on: d
    Link detected: yes
[root@dg1 ~]# ethtool eth1
Settings for eth1:
    Supported ports: [ TP ]
    Supported link modes:   1000baseT/Full 
                            10000baseT/Full 
    Supported pause frame use: No
    Supports auto-negotiation: No
    Advertised link modes:  Not reported
    Advertised pause frame use: No
    Advertised auto-negotiation: No
    Speed: Unknown!
    Duplex: Unknown! (255)
    Port: Twisted Pair
    PHYAD: 0
    Transceiver: internal
    Auto-negotiation: off
    MDI-X: Unknown
    Supports Wake-on: uag
    Wake-on: d
    Link detected: no