Wireless laptop configuration problem

David david at kenpro.com.au
Wed Aug 3 09:29:02 UTC 2005


First.. please excuse top-posting ;-)

I had a similar problem with an identical configuration (dell 
inspiron 4000, everything else the same). Although your symptoms are 
slightly different, it smells like the same problem.

Are you trying to use BOTH ethernet and wifi simultaneously? If so, you 
will have to play with the routing table, because I don't think the gnome 
config window will handle this... I could be wrong.... I'm no expert. I 
did try to get them going together and never succeeded, but it wasn't 
important to me.

If you really want just the wireless and occassionally the ethernet (which 
is my case), there seems to be a bug. 

Wireless doesn't seem to work unless eth0 is configured and active first. 
I don't know why, but I could reliably reproduce this problem. To fix it, 
I configured both ethernet and wireless to be active, but that results in 
TWO default routes and confuses everything. I couldn't convince the 
control panel to only create one default route.

I have solved this problem by inserting a simple script in /etc/inet.d and 
it now works perfectly reliably after booting. When for some reason I want 
to use ethernet I can use the gnome panel to reconfigure to ethernet and 
that seems to work OK. If I go back to wireless, after I configure the 
wireless I have to leave the ethernet active but remove the ethernet 
default route manually thus:

#route del default dev eth0

My problem had nothing to do with WEP or DHCP. I'm not smart enough to 
know what was causing the problem but my kludge fix works.

Here are my notes.. I hope they are helpful, but please note I am NOT an 
expert and in any case your problem might be a different one.

__________________________________________________________________
WIFI NOTES:

assume that ethernet was set up during the install process.

Network config panel:
ath0 properties:
essid: XXXXXX
WEP key: XXXXXXX
configure dhcp

Leave the ethernet as it was. When the system boots, both ath0 and eth0 
should be active.

KLUDGE to fix wireless route conflict.
It seems that eth0 has to be configured before ath0 will work.. who
knows why. But then Ubuntu sets up two default routes then fails.

to fix, this script goes into /etc/init.d/kludge.sh that removes the 
dodgey eth0 route. Don't forget chmod 755.

#!/bin/bash
# remove dodgey eth0 route so that ath0 will function
route del default dev eth0
echo "Kludge to remove dodgey eth0 route"

Then, to insert the symlinks in rc directories do this:
#update-rc.d kludge.sh start 41 1 2 3 4 5 S .

41 places it just after the networking is brought up. The script doesn't
conform to Debian init.d start/stop requirements, but it shouldn't matter.
Run levels 0 and 6 are shut-down/reboot, so routes don't matter.

Now reboot. wifi should be working a few seconds after the echo message 
appears, and the led's will synchronise.


__________________________________________________________________


On Sun, Jul 31, 2005 at 06:34:51PM -0700, William Chapman wrote:
> Hello!
> 
> I have an old, Gateway Solo 9300 notebook (450 MHz Pentium 3) with a
> fresh (today!) Hoary installation.  Ubuntu is doing great except for
> the wireless internet connection.  Here is the setup:
> 
> (1)  There is a NAT broadband, wireless router in the picture;
> 
> (2)  There is a built-in 10/100 Ethernet port which apparently works
> fine (eth0) (connected to wired port in NAT router);
> 
> (3)  There is a PCMCIA Netgear wireless card in the laptop which
> appears to be configured correctly (ath0), but cannot be made to talk
> on the LAN (more info below);
> 
> (4)  With both interfaces (eth0 & ath0) configured and activated, the
> System->Administration->Networking control panel wants to select eth0
> as the "Default Gateway;" if I change this to ath0, it does not
> complain, but the change is apparently not made (see (5) below);  I
> think this is an important clue;
> 
> (5) Anytime eth0 is configured and active (as indicated in control
> panel), "route -n" shows the following:
> 
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
> 192.168.0.0     0.0.0.0         255.255.255.0   U        0        0   
>     0    eth0
> 0.0.0.0             192.168.0.1 0.0.0.0               UG     0       
> 0        0     eth0
> 
> This is true regardless of the state of ath0.
> 
> (5)  If eth0 is deactivated (button push in panel) or the "is
> configured" check box is cleared (on panel), and then ath0 is set to
> the default gateway (via the selection button), "route -n" reveals a
> blank table, despite that fact that ath0 was set to the default
> gateway in the control panel.
> 
> (6)  During the entire investigation, the Network Monitor tool (small
> Gnome tool for panel - looks like the similar Windows tool - two
> overlapping displays that light up) for ath0 shows that the card is
> connected, that the signal strength is good (>85%), and that the WEP
> and MAC address limitations set in the router are being satisfied. 
> because the card shows the correct flashing green leds (steady, in
> unison) indicating a good connection with the access point.  The ssid
> and wep numbers are entered correctly.
> 
> (BTW, to enter the WEP key as an ascii string (which is ten hex
> characters), I had to do "s:xxxxxxxxxx" where the x's are ten hex
> characters.  The need to enter "s:" as a header is not obvious!!)
> 
> (5)  The Applications->System Tools->Network Tools GUI reveals that it
> knows nothing about ath0's MAC address, even though this is shown
> correctly on the Network Monitor tool.
> 
> (6)  With eth0 (wired) deactivated, attempting to ping with Network
> Tools shows that nothing is even being sent.  The system is totally
> ignoring the command.  If eth0 is active, pings go out his port; I
> can't get pings to go out ath0 (wireless) even though the
> configuration and connections seem ok.
> 
> (7)  The correct wireless ID and WEP key are entered; DHCP is
> selected, and the gateway address is 192.168.0.1 (the NAT router). 
> This approach has has always worked flawlessly with my setup,
> including wireless under WinXP.
> 
> What's going on?  It seems like Linux doesn't really want to, or
> can't, consider the wireless card as a means to get to the internet.
> 
> Any help will be appreciated!!
> 
> Bill Chapman
> 
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