[ILUG] Re: Strange problem with WiFi cards

[Gavin McCullagh]

In gmane.user-groups.linux.ilug.general, you wrote:

> I have two identical WiFi cards (Orinoco Gold PCMCIA cards).
> I use one in my laptop all the time, and it works perfectly.
> I thought I would try the other this evening,
> but for some reason it would not connect to my desktop.

Sounds from your general description that the card appears to be working,
ie the driver is installed and the card is configured.  If this is not the
case, that's clearly your problem.  However: 

> It is as though Linux somehow takes my usual card as default,
> though I don't find anything anywhere to specify that.

That's probably a routing issue.  If you have two network interfaces
enabled, linux (or any OS for the matter) has to figure out which interface
to use to connect to a given resource.  Generally there is a "default
route" setting which sets which interface to use by default.  If your
regular wired network interface is enabled and set as default route, it'll
be sending all requests down that.

The solution is to do either of:

1. set the wifi one as defaultroute
2. disable (not uninstall) your wired network card.

You're using Fedora so I'm not totally sure how this is done.  However, I'd
imagine if you route around in the network settings you may see the two
cards listed.  If you do, you should be able to disable one or set the
default route.

On the command line, you could type "/sbin/ifconfig" to see which
interfaces are active and "/sbin/route" to see the routing table.  The
latter's output should include a line which begins "default" and ends with
the interface, likely either "eth0" or "wlan0".  You can temporarily
disable the eth0 interface with "ifconfig eth0 down" (nb remove the
inverted commas). 

> I'm using dhcp, and have even specified the MAC address of the second
> card in /etc/dhcpd.conf on the desktop, but this seems to have no effect.

Well, if the info never gets to the server this obviously will not help.

> I'm disappointed that WiFi seems so much more difficult to configure
> under Linux than under Windows.

On this occasion, I don't think wifi is the problem (though for certain
cards wifi setup is indeed a PITA in linux :-).  It's a general two network
interfaces problem.  I guess Win2k has either got the other interface
disabled or guessed the default route somehow.

Gavin

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