changing speed of NIC Card in linux

Linux and Unix-Like Linux
1

Hi,

I would like to know how to change the speed of ethernet card in linux? as it is showing auto-neg using mii-tool -v eth0

and my requirement is 100mbps full duplex.

Regards,

Manoj

2

If you have it, you can see a lot of information using ethtool, eg

#  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 auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000007 (7)
        Link detected: yes

Now change that to 10MBit half duplex, no autonegotiation:

# ethtool -s eth0 autoneg off duplex half speed 10
# 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:  Not reported
        Advertised auto-negotiation: No
        Speed: 10Mb/s
        Duplex: Half
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000007 (7)
        Link detected: yes
3

If not, you might have mii-tool: Manpage of MII-TOOL

4

Is there anything wrong with the speeds you're getting? Auto-negotiation is capable of negotiating automatically to 100mbps full duplex when both transceivers are capable of it without manual intervention(and, occasionally, when they're not).