Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My GbNIC (Intel 82579LM, kernel 3.0 module e1000e) only connects with 100mbit although it's connected to a 1000mbit port (Asus GigaX1005) via an short (<3m) CAT6 cable.

flo-nbook ~ # ethtool eth0
Settings for eth0:
    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 pause frame use: No
    Advertised auto-negotiation: Yes
    Speed: 100Mb/s
    Duplex: Full
    Port: Twisted Pair
    PHYAD: 2
    Transceiver: internal
    Auto-negotiation: on
    MDI-X: on
    Supports Wake-on: pumbg
    Wake-on: g
    Current message level: 0x00000001 (1)
    Link detected: yes

Also forcing has no effect:

ethtool -s eth0 speed 1000 

Is this a known bug in the kernel module? Am I missing something? Or an interoperability problem with the Asus switch?

share|improve this question
This is useful in case anyone else makes the same mistake, but if you really want it deleted we can – Michael Mrozek Aug 18 '11 at 19:37
up vote 1 down vote accepted

According to Asus's specs on that switch, its only capable of 100mbit.

5 RJ-45 for 10/100Mbps Ethernet ports

Also you cant set ports to 1000mbit, it must be auto-negotiated.

share|improve this answer
You seem to be are right. I bought the switch some time ago and assumed because of its name that its gigabit capable. Also the "Advertised link modes" supported my assumption. – Flow Aug 18 '11 at 14:35
Ya, theyre kinda sneaky. The specs say 1.0 Gbps but thats the throughput the switch is capable of handling. A 100mbit port on full duplex does 200mbit, and then 5 ports gives you a total of 1gbit throughput. – Patrick Aug 19 '11 at 1:14

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.