How to find network interface details using Linux Mii-Tool

Both the mii-tool and ethernet tools allow Linux system administrators to modify or change or check the network interface card. Both tools can be used to diagnose and identify Ethernet devices. Even if you can control the link, set the auto-negotiation mode, set the simplex, half-duplex or full-duplex mode. (Simple, half-duplex, and full-duplex are called dialog modes, and they determine the direction of data flowing through the network media.)

Use this command to set the speed and duplex of the interface card. Make sure your NIC should support mii-tool.

1) Mii tool (default output)

By default, mii-tool displays the following results on the console.

# Mii-tool eth0: Negotiated 100baseTx-FD, link is normal

Detailed information on each card can be found using the -v option. You can find the speed of the link status of the connection.

[[email protected]]# Mii-tool -v eth0: negotiated, link normal product information: supplier 00:08:18, model 25 rev 0 Basic mode: enable auto-negotiation basic status: auto-negotiation completed, link normal function: 100baseTx-FD 100baseTx- HD 10baseT-FD 10baseT-HD Advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD Flow Control eth1: Negotiated, Link Determined Product Information: Vendor 00:08:18, Model 25 rev 0 Basic Mode: Enable Auto Negotiation basic status: auto negotiation completed, link determination function: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD Advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow control

2) Forced speed setting

The mii-tool command below will force the interface speed to 10 Mbit

# Mii-tool –force 10baseT-FD

[[email protected] ~]# Mii-tool eth0: 10 Mbit, full duplex, normal link

3) Start auto negotiation

This command will restart auto-negotiation.

# Mii-tool-restart

4) Set to full duplex

The following options change the setting of the eth0 interface to 100 Mbs full duplex:

# Mii-tool -F 100baseTx-FD eth0

Also read:

  • How to use the ethtool command by example