netstat -e/-i depending on platform.
if the counter for collissions is non-zero then the nic is in half-duplex mode.
if the coutner is 0 and there is a lot of network activity then it
is 99% probable that it is in full-duplex.
looking at a trace, look at tcp there it is easy, if you get
massive packetloss and tcp retransmissions but only in one single
direction (unidirectional packetloss)
then you might have a duplex mismatch somewhere (could be congestion also).
a duplex mismatch will show up as massive packetloss in one direction,
in the direction from the fullduplex towards the halfduplex
interface on the link where the mismatch is.
On Mon, 15 Nov 2004 15:55:47 +1030, David Ruwoldt
<david.ruwoldt@xxxxxxxxxxxxxxx> wrote:
> Dear All,
>
> Is there any way to work out what duplex the NIC is running at from a
> packet capture. I have been looking for a windows utility on google to
> tell me what duplex a NIC is running on but have not found one yet.
>
> Yours sincerely
>
> David Ruwoldt
> --
> David Ruwoldt
> Team Leader, Operating Systems & Services
> Information Technology Services
> Level 7, 10 Pulteney St
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> AUSTRALIA
>
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