Find the speed of your Ethernet card in Linux

Find the speed of your Ethernet card in Linux

as usual there are more than one way to do it

# dmesg|grep eth3
igb 0000:07:00.1: eth3: (PCIe:2.5Gb/s:Width x2) 00:21:28:d7:a0:cf
igb 0000:07:00.1: eth3: PBA No: 1040FF-0FF
igb: eth3 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX

# ethtool eth3
Settings for eth3:
Supported ports: [ TP ]
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: 1000Mb/s
Duplex: Full
Port: Twisted Pair
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0x00000003 (3)
Link detected: yes

# mii-tool -v eth3
eth3: negotiated 100baseTx-FD, link ok
product info: vendor 00:aa:00, model 57 rev 1
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD

# mii-diag -v eth3
mii-diag.c:v2.11 3/21/2005 Donald Becker (
Using the new SIOCGMIIPHY value on PHY 1 (BMCR 0x0000).
The autonegotiated capability is 01e0.
The autonegotiated media type is 100baseTx-FD.
Basic mode control register 0x1140: Auto-negotiation enabled.
You have link beat, and everything is working OK.
This transceiver is capable of 100baseTx-FD 100baseTx 10baseT-FD 10baseT.
Able to perform Auto-negotiation, negotiation complete.
Your link partner advertised c1e1: 100baseTx-FD 100baseTx 10baseT-FD 10baseT.
End of basic transceiver information.

MII PHY #1 transceiver registers:
1140 792d 02a8 0391 0de1 c1e1 000d 2801
489a 0200 3800 0000 0000 0000 0000 3000
01a0 ce04 1600 400f 0005 3323 0000 0850
0514 019d 0000 0080 2f40 0000 0000 0000

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