Re: [tlug] WiFi roaming and open networks

[Christian Horn <chorn@example.com>]

On Mon, May 05, 2008 at 07:45:44PM +0900, Dave M G wrote:
> 
> Okay, so I went down to the same place where I encountered the Mac guy 
> who was successfully getting some WiFi action, and fired up the laptop.
Hope something useful comes out here if you are even moving around
for debugging..

> dave@example.com:~$ ping www.heise.de
> ping: unknown host www.heise.de

> dave@example.com:~$ iwconfig
> [...]
> eth0      no wireless extensions.
> [...]
> eth1      IEEE 802.11g  ESSID:"V110-c3b851"
>           Mode:Managed  Frequency:2.452 GHz  Access Point: 
> 00:80:87:F3:91:7F
>           Bit Rate:54 Mb/s   Tx-Power=20 dBm   Sensitivity=8/0
>           Retry limit:7   RTS thr:off   Fragment thr:off
>           Power Management:off
>           Link Quality=67/100  Signal level=-60 dBm  Noise level=-90 dBm
>           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>           Tx excessive retries:0  Invalid misc:0   Missed beacon:19
> 
> Hmm... I'm not sure what to make of this. The eth1 thingy seems to be 
> talking to someone, but I don't quite get why there is an eth0 and eth1. 
Looks like you made it to connect to the accesspoint.

> Shouldn't I have just one wireless device?
eth0 is you rj45-networkchip.

> dave@example.com:~$ ifconfig
> [...]
> eth1      Link encap:Ethernet  HWaddr 00:0e:35:ac:01:5b
>           UP BROADCAST MULTICAST  MTU:1500  Metric:1
>           RX packets:282 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:42 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:0 (0.0 B)  TX bytes:3397 (3.3 KB)
>           Interrupt:7 Base address:0x8000 Memory:e0200000-e0200fff
> [...]
There have been packets received and sent but apparently you
didnt get an ip via dhcp.

> There's only one other thing I could add. Inside Ubuntu under 
> System->Administration->Hardware Testing, there's a utility to test 
> hardware. The network device test returned this error:
> [...]
Error because you didnt get a gateway assigned, ok.

> That's about it. Does any of this shed any light?
Seems like your distros network-connection-utility successfully
triggered connection to the accesspoint. The layer on top of that is
getting ip/gateway/netmask and other informations.

- Try to find out if your distro started something to get the
informations via dhcp. Look for 'dhcp' in systemlogs:
   sudo grep dhcp /var/log/* | less
or see if programs are running to get dhcp-infos:
   ps ax|egrep 'dhcp|pump'

- If such programs are running you could kill those using
   sudo killall dhclient pump

- Or try to start them yourself:
   sudo dhclient eth1

These commands are independent from distribution, i have no ubuntu
for testing. Probably others here know what tools ubuntu is using
for this at the moment, and what logfiles could be interesting.


Christian