linux下如何判断网卡是千兆还是万兆

1、ethtool

ethtool 网络接口名

#ethtool em4(网络接口名)

Settings for em4:

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 pause frame use: No

Advertised auto-negotiation: Yes

Speed: 1000Mb/s

Duplex: Full

Port: Twisted Pair

PHYAD: 1

Transceiver: internal

Auto-negotiation: on

MDI-X: Unknown

Supports Wake-on: g

Wake-on: d

Link detected: yes

2、查看网卡实际通讯速率

dmesg | grep eth0

这个命令可以列出网卡工作速率。看到 Up 1000Mps full duplex 就知道是千兆网卡了。

（这里 eth0是网卡的设备名，不同机器名称可能不同。可以用ifconfig 查看自己网卡的设备名）