WIFI connection drops

[tico]

Studing Tiny Core since a week. Love it! USB install only. CorePlus.

I've read the online book.

The problem I have is that wifi connection works a few minutes, then drops. This happens while using opera 9.
At some point web pages don't load anymore, ping doesn't work anymore as well.

Restarting wifi from the icon bar I'm prompted for:

• disconnection, 
• then AP selection,

then after connection wifi works again. A few minutes later connection drops again.

Troubles above can be reproduced with Tiny Core on three different laptops, same AP. Each of them doesn't have any wifi problem with the native OS (XP, Vista, Seven), same AP.

Not much Linux experience. Searched about wifi problems on the forum but most topics seem to deal with inital connection, not connection dropping later.

Please help... THANK YOU.

[gerald_clark]

I would check for duplicate IP addresses on the network.

[tico]

I would check for duplicate IP addresses on the network.

Thank you, I'm investingating as suggested. I'm sure that earlier the Tiny Core host was always the only host in the network (unless the AP was hacked by someone else). After your suggestion I tested two hosts side by side and verified DHCP assigned two different IP's correctly (one for the TC host, one for a Seven host).

What's new is that this time I was able (by chance) to reproduce the problem exactly:

instead of using opera9 just fired a terminal and let ping run uninterrupted for 15 minutes. The connection didn't drop. Then I stopped ping and moved to this other pc to write a reply on the forum.

A few moments ago I checked the TC Terminal on the other pc to restart ping BUT the connection is gone. It looks maybe like an inactivity timeout or something like that...

Is there such a feature in TC?

Please consider that this happens on three different pcs from three different brands, isn't it  somewhat unlikely that the wifi hardware goes to sleep by itself due to power management (or that's a driver issue) ?

[tico]

More evidence. Probably not a wifi connection problem, sorry.

What happens is that when connection seem to drop actually host names can't be resolved but ping to numeric ip addresses continues to work. Tried to issue an nslookup command but unespectedly it worked fine and at the same time (by chance?) host names were resolved again.

There seem to be several variables to keep under control to reproduce and understand the problem. More suggestions welcome, thanks.

Apparently disconecting and reconnecting to the AP via wifi resets something and solves the problem for a few minutes.

[nitram]

I was just going to suggest trying different router channel(s) or set to 'auto', but you seem to be narrowing down to a DNS issue?

[curaga]

When you get DNS issues, try another DNS server, for example Google's.

nslookup facebook.com 8.8.8.8

[tico]

When you get DNS issues, try another DNS server, for example Google's.

nslookup facebook.com 8.8.8.8

Thanks, I'll try that too. Unfortunately the DNS issue was misleading... when the DNS server responded again the TCL host worked for another 15 minutes then, this time, neither dnslook nor ping worked anymore. The funny thing is that the problem is perfectly reproductable but my tests are inconclusive: I need to learn how to better collect evidence when the problem happens....

I'm too excited about Tiny Core to give up. That's the OS I was looking for since 20 years (25?)... Thanks for this beautiful forum.

[tico]

I was just going to suggest trying different router channel(s) or set to 'auto', but you seem to be narrowing down to a DNS issue?

Interesting! Actually the DNS behaviour was possibly misleading, please see my other post above.

I said "Interesting!" as, if I disconnect and reconnect the wifi link (my original procedure) the list of available AP's each time seems DIFFERENT from the one displayed some 10/15 minutes earlier. Channel overlapping as people switch on/off their AP's here around? My AP channel selector is always on "auto", so far. Thanks.

[nitram]

I said "Interesting!" as, if I disconnect and reconnect the wifi link (my original procedure) the list of available AP's each time seems DIFFERENT from the one displayed some 10/15 minutes earlier. Channel overlapping as people switch on/off their AP's here around?

That's my experience too. Suspect it depends on signal strength, interference, others turning routers on/off.

My AP channel selector is always on "auto", so far. Thanks.

If you have admin rights, would only take a couple minutes to try a dedicated channel. Believe using a channel above 11 is a known issue on some Linux distributions, so if your router is set to auto and is able to provide channels >11 you should confirm which channel you're using.

Have you checked iwconfig to confirm power management is turned off?

Have you tried a manual wifi connection via wpa_supplicant? Provides solid wifi on my TinyCore netbook:
http://w1.fi/cgit/hostap/plain/wpa_supplicant/README

A little trickier if you use a hidden network:
http://forum.tinycorelinux.net/index.php/topic,17950.0/nowap.html

Maybe some of this helps or not...just trying to help out.

[tico]

My AP channel selector is always on "auto", so far. Thanks.

If you have admin rights, would only take a couple minutes to try a dedicated channel. Believe using a channel above 11 is a known issue on some Linux distributions, so if your router is set to auto and is able to provide channels >11 you should confirm which channel you're using.

Yes, channels >11 are provided. Yesterday I locked the AP to channel 1 but still had connection problems. Today I took a couple of laptops (Tiny Core and Seven) to another building to test them side-by-side with another AP. They both worked flawlessly.

When I brought them back to the original AP, I also changed the locked channel from 1 to 8 (just because listing other AP's here around that channel was not used). Well, Tiny Core worked fine for three hours, then I ended the experiment. Great, many thanks!

While experimenting I was thinking that, if wifi.sh solved my troubles by disconnecting and reconnecting:
1) I better study the script and learn how to control wifi from command line
2) in worst case, I could prepare a simpler, non interactive, script to be execute periodically to disconnect/reconnect
3) if all three laptops that had wifi problems with TC work fine with windows (three different versions) maybe my TC installation is missing some form of "retry" procedure/config-param which is supported by the other os?

In any case I find studing the wifi implementation in TC very interesting, so I'll keep reading more on this even if the problem won't show up anymore.

Have you checked iwconfig to confirm power management is turned off?

Yes, that's among the first things I was looking for when experimenting with iwconfig. Always off.

Have you tried a manual wifi connection via wpa_supplicant? Provides solid wifi on my TinyCore netbook:
http://w1.fi/cgit/hostap/plain/wpa_supplicant/README

Not tried directly yet, but reading wifi.sh it seems to me that the script does use it so I was probably using it from the beginning.

A little trickier if you use a hidden network:
http://forum.tinycorelinux.net/index.php/topic,17950.0/nowap.html

No hidden network here but a very interesting read. Also, useful links in that thread.

Maybe some of this helps or not...just trying to help out.

You helped A LOT. Thanks!