How to know duplex mode?

How can I know if a given wired connection is in full or half duplex?
I know how to check the settings but most adapters are set to auto-
negotiate and I don't know what was negotiated. Some switches will
tell you on their status lights but there's got to be a way to query a
system and get it to say if it's running in full or half. I"ve
searched everywhere and just find tons of answers about how to change
settings on a card. That doesn't give me a way to check the current
state. Thanks.

njem wrote in

m:

How can I know if a given wired connection is in full or half
duplex? I know how to check the settings but most adapters are set
to auto- negotiate and I don't know what was negotiated. Some
switches will tell you on their status lights but there's got to
be a way to query a system and get it to say if it's running in
full or half. I"ve searched everywhere and just find tons of
answers about how to change settings on a card. That doesn't give
me a way to check the current state. Thanks.


That detail is buried in the driver details. AFAIK, there is no
standard Windows driver interface that extracts this information from
whatever manufacturer's network card/driver that you use. Having said
that, I believe that *some* manufacturer's drivers generate a System
Log message declaring this information that you can look up using the
Event Viewer (Start - Run - "eventvwr.msc"). For example, my
computer has an Intel network card/chipset and I see the following
Information message in my System Event log at startup:

Intel(R) 82567LM Gigabit Network Connection Link has been established:
100Mbps full duplex.

HTH,
John

*For example, my
computer has an Intel network card/chipset and I see the following
Information message in my System Event log at startup:

Intel(R) 82567LM Gigabit Network Connection Link has been established:
100Mbps full duplex.

Excellent idea. I just checked a few systems and most had some similar
report. One with an Intel NIC gives a generic report about connecting
but no details.

Thanks.