Check duplex (auto-negociation) on Windows

The ipconfig doesn’t print the result of auto-negociation. At least on Windows XP SP2 and Windows Se7en.

To check the result of the auto-negociation process, open the Event Viewer, select the System journal and check the events that have the network driver name as source.

Here’s an example from Windows Se7en on my Lenovo IdeaPad S10:

Log Name: System
Source: b57nd60x
Date: 17/03/2009 20:08:59
Event ID: 9
Task Category: None
Level: Information
Keywords: Classic
User: N/A
Computer: karuna
Broadcom NetLink (TM) Fast Ethernet: Network controller configured for 100Mb full-duplex link.

That’s all folks !


  • Joel Carnat Tue, 15 Nov 2011 20:29:12 +0000 Reply

    I just applied a new firmware so that Freebox Player runs 1.1.2. But the issue is still there with AirPort 7.6 ; although the 1.1.2 Changelog claims “autonegociation problem solved” :-/

  • chocho63 Thu, 20 Sep 2012 13:19:28 +0000 Reply

    On HP Servers, you can use C:\Program Files\HP\NCU\HpNetSvy.exe to check Duplex
    On IBM Servers, you can use C:\Program Files\Broadcom\BACS\bacscli.exe

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