目前用過的兩個命令：

1、ethtool

ethtool 網路介面名

#ethtool em4
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、lspci  

當前是博通BCM5709千兆網絡卡Gigabit（萬兆網絡卡顯示為10-Gigabit）

#lspci -vvv | grep Ethernet
01:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit

Ethernet (rev 20)
Subsystem: Dell PowerEdge R710 BCM5709 Gigabit Ethernet
Product Name: Broadcom NetXtreme II Ethernet Controller
01:00.1 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
Subsystem: Dell PowerEdge R710 BCM5709 Gigabit Ethernet
Product Name: Broadcom NetXtreme II Ethernet Controller
02:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
Subsystem: Dell PowerEdge R710 BCM5709 Gigabit Ethernet
Product Name: Broadcom NetXtreme II Ethernet Controller
02:00.1 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
Subsystem: Dell PowerEdge R710 BCM5709 Gigabit Ethernet
Product Name: Broadcom NetXtreme II Ethernet Controller
pcilib: sysfs_read_vpd: read failed: Connection timed out

小知識：

Gigabit是資料儲存的單位，通常用符號Gbit或Gb表示。它的換算公式：1 Gb = 10的9次方 bits = 1,000,000,000 bits 。 另一個常見的單位是Gibibit，gibibit是用來表示二進位制換算的，1 gibibit = 2的30次方 bits = 1,073,741,824 bits。