Green0 is stuck at 100Mbps, ethtool will not change the speed

Networking
1

As the title says, I cannot increase the speed of the network interface green0.

[root@bouncer ~]# ethtool green0
Settings for green0:
        Supported ports: [ TP ]
        Supported link modes:   100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
                                2500baseT/Full
                                5000baseT/Full
        Supported pause frame use: Symmetric
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  1000baseT/Full
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Auto-negotiation: on
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        MDI-X: Unknown
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes
[root@bouncer ~]# ethtool -s green0 autoneg off speed 1000 duplex full
[root@bouncer ~]# ethtool green0
Settings for green0:
        Supported ports: [ TP ]
        Supported link modes:   100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
                                2500baseT/Full
                                5000baseT/Full
        Supported pause frame use: Symmetric
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  1000baseT/Full
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Auto-negotiation: on
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        MDI-X: Unknown
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes
[root@bouncer ~]#

What else can I try?

2

Hi @cuphi.

It’s is very strange.

May be for this causes:

  • Badly state of cable.
  • Cable category incorrect (category 5 or under).
  • Badly state of switch or router.
  • Switch or router only works in ethernet mode and not giga.

To try to know whats happend, try conect one PC or Laptop with Giga-ethernet port to Green0 and check again with “ethtool” command.

Say us.

Regards.

2 Likes
3

For 1000BASE-T and above, you can not switch off autonegotiation.
And if the speed is limited to 100Mb/s this setting comes from the other side of the connection. So it doesn’t make sense to set a higher speed ( both sides of a connection must use the same speed, this is true for ethernet also ).

Do have an old switch attached to green0?

4 Likes