How to check the speed of your network card

[brent]

In this tip we will see how to use the terminal to check and change the current speed of your network card under Ubuntu or any Debian-based system. This tip will be useful for those having incorrect network card speed that is running for example at 100Mb/s rather than 1000Mb/s.

To check the current network card speed, we will use the "ethtool" command line utility. To install it under Ubuntu/Debian, run the following command:

sudo apt-get install ethtool

Replace "eth0" with your own network interface (eth1, eth2, etc.). Here are the outputs returned for my system (speed is displayed under the "Advertised auto-negotiation (...) line):

~$ sudo ethtool eth0
Settings for eth0:
 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: 100Mb/s
 Duplex: Full
 Port: Twisted Pair
 PHYAD: 0
 Transceiver: internal
 Auto-negotiation: on
 MDI-X: Unknown
 Supports Wake-on: umbg
 Wake-on: d
 Current message level: 0x00000007 (7)
          drv probe link
 Link detected: yes

To change for example the speed of your network card from 100Mb/s to 1000M/s, run this command:

sudo ethtool -s eth0 speed 1000 duplex full autoneg off