Comments on: Linux change the speed and duplex settings of an Ethernet card

By: Jon

Jon — Fri, 27 Jan 2012 21:04:48 +0000

I have Red Hat RHEL 5.5 and when I use the ethool
# ethtool -s eth0 speed 1000 duplex full
I get the erro of :
Cannot set new settings: Invalid argument
not setting speed
not setting duplex
Is this a bug in RHEL 5.5? It worked in RHEL 4.8

By: daksh

daksh — Wed, 27 Jul 2011 18:57:47 +0000

yeah really it works…, thanks a lot.
Actually i was looking it from centos help sites, but i got only dust there,

now i tried it, And my net is working,
it is working of 10bastT-HD

Thanks for supporting code in this simple manner…

By: Jadiyappa

Jadiyappa — Thu, 21 Apr 2011 11:13:46 +0000

I changed the full duplex to half duplex using command
/sbin/ethtool -s eth0 speed 10 duplex half

but if do
/sbin/ethtool eth0 getting o/p: as below :
/sbin/ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0×00000033 (51)
Link detected: yes
that indicates my PC is not getting changed to half duplex

Pls help me what i have to do?

By: sanjay

sanjay — Tue, 06 Jul 2010 06:41:30 +0000

i commends is very useful thankx to all.

By: Vivek Gite

Vivek Gite — Tue, 25 May 2010 19:31:56 +0000

VMWarw is known to have a few issues with ethtool. Try
ethtool -i vmnic0
And esxcfg-nics command can also help.

HTH

By: Joe Wulf

Joe Wulf — Tue, 25 May 2010 16:39:48 +0000

So, other than eth-tool and mii-tool……….. are there any other *creative* ways to determine NIC speed, from within the system at the command line?

R,
-Joe

By: Joe Wulf

Joe Wulf — Mon, 24 May 2010 20:21:42 +0000

Hmm, my previous attempt to say this seems to have gone off into the ether (but not eth). :)

Thank you, too—and your are welcome as well, Vivek Gite. I appreciate the quick response!
However, I’ve no joy with using the ‘mii-tool’ you’d suggested.

‘ethtool eth0′ returns only the following output:
“Settings for eth0:
Current message Level: 0×00000007 (7)
Link Detected: yes”
—-and nothing further.

‘dmesg | less’ and manually searching for eth0 returns only the following:
“divert: allocationg divert_blk for eth0
eth0: registered as PCnet/PCI II 79c970a
eth0: no IPV6 routers present”

‘mii-tool eth0′ returns only the following:
“SIOCGMIIPHV on ‘eth0′ failed: Operation not supported.”

I get this, primarily on VMs within an ESX 3.5.0 host.

R,
-Joe Wulf

By: Vivek Gite

Vivek Gite — Mon, 24 May 2010 19:23:05 +0000

Try mii-tool.

And thanks for heads up. I’ve fixed the problem with date and time. Now comment displays the date properly for all posts.

By: Joe Wulf

Joe Wulf — Mon, 24 May 2010 18:52:24 +0000

On RHEL ES4u6 32bit, when I execute “ethtool eth0″ it does NOT give me the speed, which I desire to know. I’ve played with the options, but don’t see anything obvious that forcefully provides information on the nic/link speed.

Any other option/method for determining, via the CLI the nic/link current speed?
Thanks

Message submitted 2010/05/24 @ 14:45 EST (as the article and messages don’t indicate their date of posting)

By: Bob

Bob — Mon, 15 Mar 2010 23:28:45 +0000

This command does not seem to be working with Centos 4.5 Final

ethtool -s eth0 speed 100 duplex full

It locks up the NIC. I was able to SSH in from the secondary port and reboot the server gracefully.

Prior to changing the speed and duplex mode I get:

[root@hw000 vz-scripts]# 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: Half
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: umbg
Wake-on: g
Current message level: 0×00000007 (7)
Link detected: yes

Then I enter and it hangs:

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: 100baseT/Full
Advertised auto-negotiation: Yes
Speed: Unknown! (65535)
Duplex: Unknown! (255)
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: umbg
Wake-on: g
Current message level: 0×00000007 (7)
Link detected: no

- Ethernet controller: Intel Corporation 82541GI Gigabit Ethernet Controller
- Ethernet controller: Intel Corporation 82547GI Gigabit Ethernet Controller

By: Philippe Petrinko

Philippe Petrinko — Wed, 06 Jan 2010 14:33:10 +0000

Hi Vivek,

As you pointed out, mii-tools may be deprecated, so
would you mind modifying accordingly your very interesting topic,
and consider adding what Mage767 has most conveniently added:
How to switch off auto-negocation using ethtool :
# ethtool -s eth0 autoneg off

So, to sum uop, either you are lucky enough to do both action alltogether:
# ethtool -s eth0 duplex full autoneg off
(this works for my Ethernet Card)

Either you need to do it in 2 steps:
# ethtool -s eth0 autoneg off
# ethtool -s eth0 duplex full

Thanks for your anwser – BTW you brought up a solution I had been wondering for months !
– Philippe

By: Fabrizzio

Fabrizzio — Mon, 12 Oct 2009 17:00:13 +0000

Alexey, I had the same problem.
You need to turn off autoneg to use a sub-optimal speed.
ethtool -s eth0 autoneg off speed 10 duplex half

By: David Baron

David Baron — Tue, 18 Aug 2009 17:21:24 +0000

Very useful article! Trying any of this leaves me with no link, no connection. I can run 10mb/s half duplex, autonegotiated. Attempts to force, no auto yield no link. No response to pon.

I am running Debian Sid, NIC ethO –>pptp pppO to ASDL modem.

By: Hector

Hector — Fri, 22 May 2009 15:36:53 +0000

Super now my Debian is work with my internet, I was change of 100TX to 10T , but Now I like to create one script that when restart my Debian is work my internet, the question is How I’ll create the Script? please any one there help me and send my same example or the solution.

Thanks for the post.

By: V.Balaviswanathan

V.Balaviswanathan — Mon, 27 Apr 2009 13:42:34 +0000

Cool one……..Thanks for the post

By: Christian Peper

Christian Peper — Thu, 15 Jan 2009 10:01:57 +0000

@kanon
1000Base-T requires the use of auto nego. So perhaps the switch you’re using doesn’t offer it and the NIC decides to fallback to 100Mb? Just an idea…
Chris

By: kanon

kanon — Mon, 05 Jan 2009 20:48:14 +0000

My 1gbit card refuses to report 1gbit. GRRRR! I use the ethtool, but at no vail. The mii-tool dont do to much for my Debian system either.
Might be a stupid question, but are there some config settings for the network file? Im sure I had it running at 1gbit, but I also remember it was a hassle to get it to run at that speed.
Well, off to google again.. :)

By: westea

westea — Fri, 26 Dec 2008 23:55:18 +0000

I have a Dell laptop (Precision M6300) with Broadcom NetXtreme ethernet controller and
a wireless Dell WLAN Mini card. I had Fedora installed and can dual boot Windows XP or Fedora. I decided to start with the Broadcom controller since many of the Web sites imply
that the wireless ethernet on linux can be frustrating. Unfortunately, the “wired” ethernet is
also proving to be a problem. I will try the tools you have listed and hope. Certainly the
Administor->network-> gui interface did not work. Tried the tg3 driver but when I activate
it, it says it is not there. Of course I am sending this email thru the BroadCom controller but
with the XP OS. There seems to be a big difference between a linus USER and Admin. Oh well
I will reboot and try some of your suggestions.

By: fsaenz

fsaenz — Sat, 13 Sep 2008 11:01:13 +0000

There is way to “fix” the speed on a gig-ethernet NIC while complying with the standard, based on the last paragraph of the article mentioned above by Shawn (http://standards.ieee.org/reading/ieee/interp/IEEE802.3af-2003interp-6.pdf):

# ethtool -s eth0 speed 1000 duplex full autoneg on

The NIC keeps the auto-negotiation but only advertises 1000mbps. It works fine.

By: Shawn

Shawn — Tue, 15 Jul 2008 22:01:35 +0000

On Red Hat Enterprise, and SuSE Enterprise (and probably others) you can include the options in your interface config file using the ETHTOOL_OPTS argument:
# red hat: /etc/sysconfig/network-scripts/ifcfg-eth0
# sles: /etc/sysconfig/network/ifcfg-eth-id-{mac address}
ETHTOOL_OPTS=”autoneg off speed 100 duplex full”

Note that you cannot disable autonegotiation on gig-ethernet over copper. Autonegotiation is REQUIRED in the 802.3ab definition (http://standards.ieee.org/reading/ieee/interp/IEEE802.3af-2003interp-6.pdf)