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Changing default Ethernet connection rate? Network
I have two Macintosh computers at home and I have them interconnected with each other using a router, (Netgear RT 314), my problem is that my newest Mac is a G4 Cube with auto negotiation on the ethernet port. The router also uses auto negotiation and neither computer nor router will talk to each other. This problem was solved using a utility called "Duplexer Tool" which works fine in OS 9.1, and that solved my ethernet problem by setting my G4 cube to 10 Mb/s, and letting the router set itself to the same speed.

I cannot do this in OS X as the Duplexer tool only works in OS 9.1, now in OS X there is a command "ifconfig" which seems to address this problem, but I do not know how to configure this to set my Ethernet port to 10 Mb/s. Can anyone help me, and is this a fairly common problem?

Thank you.
Paul Cooper

[Editor's note: About the only value I can add here is that there's a file called "iftab" in /etc that needs to be edited. It contains this line:
en0     inet    -AUTOMATIC-
which needs to be changed to specify the connect rate, I would imagine. Anyone have any info to help configure an Ethernet card manually?]
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Ifconfig Suggestion
Authored by: DaveS on Jul 24, '01 09:11:19AM

Mac OS X does still contain the BSD man pages.

You might take a look at them by opening a terminal and then typing in 'man ifconfig'.
It should indicate a switch of 'media type', perhaps set it to 10baseTX and test it?

My best guess w/out the OS in front of me . . .


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Ifconfig Suggestion
Authored by: magill on Jul 25, '01 02:15:48PM

As best as I have been able to find out so far, it is not possible to force the configuration of duplex settings under the current Darwin code. Ifconfig simply does not support an appropriate action.

Make certain that you submit a request to Apple Mac OS X Feedback ( fix this shortcoming.... cite the Duplexer
article in the TIL. [Article Number 60436.](

Hopefully it will get fixed in 10.1

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Ifconfig Suggestion
Authored by: pcooper on Jul 28, '01 05:03:45PM


Thank you for your reply,

I have already tried the 'ifconfig manual' , but it does not indicate any way to change the media type, also the date of the manual shows June 1, 1994, which may predate auto cofiguration of ethernet ports.


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Auto-detect and Auto-Negotiate
Authored by: magill on Jul 25, '01 02:50:58PM

The Etnernet interface has two different actions which it accomplishes when an interface is powered up. The two are frequently lumped together as one, but they behave very differently.

Auto-speed-detection works in virtually every case. The NIC card looks to see what speed the incoming connection is running at and will match it. This works fine even if the switch side (or the NIC side) is "hard set" to a specific speed.

Auto-duplex-negotiation, however, is a very different problem. By definition -- if a switch port is hard set to "full-duplex," the NIC card must also be hard-set. Why? Because the spec states that if either end refuses to "negotiate," default to half-duplex!

Duplexer addressed this problem for the Classic Mac OS. We're still waiting for a similar fix (ie a modification to ifconfig) to solve the problem under OS X.

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