ethtool 工具关于网络协商功能介绍；
ethtool - Display or change ethernet card settings（ethtool 是用来显示和更改网卡设置的工具）；这个工具比较复杂，功能也特别多。由于洋文比较难懂。所以我们还是把网络设备协商方式的设置方法说一说。
2.1 ethtool 显示网络端口设置功能；
这个功能比较好办。就是ethtool 后面直接接网絽接口就行；比如下面的例子；
[root@localhost ~]# 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: No 注：自动协商关闭
Speed: 100Mb/s 注：速度 100Mb
Duplex: Full 注：全双工
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00000007 (7)
Link detected: yes 注：eth0已经激活；
2.2 ethtool 设置网卡的协商模式；
在ethtool的-h帮助中我们查看到有这样的帮助信息；
ethtool -s DEVNAME /
[ speed 10|100|1000 ] /
[ duplex half|full ] /
[ port tp|aui|bnc|mii|fibre ] /
[ autoneg on|off ] /
＊ 实例一： 把网卡eth0 速度改为10Mb/s，采用半双工；
[root@cuc03 beinan]# ethtool -s eth1 speed 10 duplex half
[root@cuc03 beinan]# ethtool eth1
Settings for eth1:
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: No
Speed: 10Mb/s 注：速度 10M/s
Duplex: Half 注：半双工
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00000007 (7)
Link detected: no 注：eth1没有激活；
＊ 实例二： 把网卡eth0 速度改为100Mb/s，采用全双工；
[root@cuc03 beinan]# ethtool -s eth1 speed 100 duplex full
[root@cuc03 beinan]# ethtool eth1
Settings for eth1:
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: No
Speed: 100Mb/s 注：速度 100M/s
Duplex: Full 注：全双工
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00000007 (7)
Link detected: no 注：eth1网卡没有激活；
命令描述：
ethtool 是用于查询及设置网卡参数的命令。
使用概要：
ethtool ethx //查询ethx网口基本设置，其中 x 是对应网卡的编号，如eth0、eth1等等
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] [duplex half|full] [autoneg on|off] //设置网口速率10/100/1000M、设置网口半/全双工、设置网口是否自协商
使用举例：
1）[root@linux /]# ethtool eth1
Settings for eth1:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal