Trouble with WiFi/Broadband

Peter Garrett peter.garrett at optusnet.com.au
Sun Feb 10 19:28:39 UTC 2008


On Sun, 10 Feb 2008 18:40:11 +0000
Rosalind Mitchell <rcm at swimbarrow.co.uk> wrote:

> Since last November I have been operating my computer wirelessly, using
> an eTec ADSL router in my bedroom where the phone input is, and a Belkin
> wireless adapter attached to my computer in my work room.  Before going 
> wireless I was using a Linksys ADSL2 wired adapter and working in the 
> bedroom.  This wasn't very satisfactory, and that's why I went wireless.
> This arrangement has been working fine until a week ago.

Have you changed anything relating to wireless or networking? Perhaps
installed something? Alternatively, perhaps there has been an update to
some program - have a look at the History in Synaptic.

System -> Administration -> Synaptic Package Manager

File -> History

 [snips]

> That night I left the computer running, with the idea of determining at what
> time the broadband went off.  So, on Wednesday morning I got up, checked
> the computer, and...  everything was fine.  On Wednesday night I left the
> computer running again and on Thursday everything was hunky-dory again. 
> This morning I got up, switched on, and...  no broadband.  As it was Sunday
> I decided to disconnect everything, give the box a thorough de-dusting, and
> fire it up again.  No broadband.  So I disconnected the Belkin adapter and
> the eTec router, wheeled the computer through to my bedroom on its trolley,
> dug out the Linksys wired router and hooked it up.  Yay!  Broadband working
> fine! So, I disconnected the Linksys, reconnected the eTec and the Belkin, 
> and... nothing.

So, it sounds like the wired interface ( probably eth0 ) is getting an IP
address, and perhaps the wireless interface is not. Also, notice that when
you leave the system running *after* the 'Magic Hour' it continues to
work the following day, which suggests that whatever process runs at 4:30
or 5:30 etc. "fixes" it, but that from a cold start that process ( whatever
it might be), does not run until late afternoon.

What happens if you run

iwlist scan   ?

That should show information about your wireless interface, including Mac
address, ESSID, etc.

Compare also the result of

ifconfig

when the wireless is working/ not working. 

[snip]
>  It seems, then, 
> to be related to light conditions and/or weather conditions.  But, it wasn't 
> doing this at all until a week ago, and at this rate, come June at this 
> latitude I won't get any work done.  

This is not very likely :)  Much more likely is that there is a process
that runs at around that time each day, and has the result of "waking up"
your wireless interface. Probably a "cron" job, but this is a guess,
really.

> What else might it be, do you think?  
> Sunspots?

Cosmic rays! Must be it!  (When you hear hoof beats, do you have a tendency
to think of zebras? <grin> )
> 
> Can anybody throw any light on what is going on here?  I really don't want to 
> move my workstation back into my bedroom if I can help it.

Another suggestion: when the wireless is "down", what happens if you issue

sudo dhclient  ?

That should attempt to connect whatever interfaces you have, by requesting
an address from your router/ wireless access point. If the connection
returns when you do that command, at least we have more to go on. You
presumably have two interfaces ( wired/ wireless ). Issuing the command as
I gave it above will fail for one, and try the other. A more specific way
is to give the interface name - what your wireless interface is called
depends on your card. For example, here mine is eth1, but yours could be
ath1 or something else. I don't know what a Belkin card uses...

Another question: are you using the Network Manager ? I 'm thinking that
you use KDE, since you are using Kmail ?  If you are using the network
manager, is there an icon in your "system tray" for it? Have you tried
turning it off/on  when the wireless fails?

Peter

-- 
"INX Is Not X" Live CD based on Ubuntu 7.04 : http://inx.maincontent.net
Screenshots slideshow: http://inx.maincontent.net/album/1.png.html
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