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oxygen_wobble

Member

Registered: 2012-05-20

Posts: 128

WLAN (iwlwifi) - no connection/route after bandwidth change ?

EDIT: Ok, after i checked this for the third time in a row, i quite sure the belowmentioned problem has got something to do
with the routers bandwith change, as there's always this message in dmesg:

[86274.220204] wlp3s0: AP 9c:80:df:7e:5c:f6 changed bandwidth, new config is 2472 MHz, width 2 (2462/0 MHz)

Hi everybody,

i'm currently experiencing massice connection problems with my router (o2 box 6431) again.
After a while (sometimes 30min, sometimes several days), my internet connection stops working.

Wlan connection to router works fine, but all DNS information seems lost (can't even ping the router BY IP, let alone
any other site).

The strange thing is, it ONLY happens with linux devices. Whilst the connection is stuck on my Laptop (arch),
my previous laptop (arch),and on my Phone (Ubuntu Touch), it works with any other device, from my android tablet, ipads, windows
machines.

Once i re-start the router, things work fine for a while.

It didn't happen that often during the last months, but now again with increasing frequency.

I don't really know where to look for further information, dmesg doesn't contain any relevant info, as it seems ...

Anyone experiencing the same ?

Regards,
n

Last edited by oxygen_wobble (2015-05-17 17:40:44)

nomorewindows

Member

Registered: 2010-04-03

Posts: 3,368

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

It has connecting with commercial cisco routers (schools, hotels), but the dns can be fixed (just rewrite /etc/resolv.conf, maybe from a copy). Much of it comes from undocumented tunables that Linux developers don't have access to but are in binary blobs with Windows and others.

Last edited by nomorewindows (2015-05-04 20:06:44)

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oxygen_wobble

Member

Registered: 2012-05-20

Posts: 128

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

Hmm ok ... i'm not really experiencing troubles with other Wlans (university etc.)

fukawi2

Ex-Administratorino

From: .vic.au

Registered: 2007-09-28

Posts: 6,224

Website

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

Are you pinging your router by IP or name? Compare the output of the commands below between when it is working and when it is not (so, run them now and save a copy of the output for later).

ip a s
ip r s
ip n s
cat /etc/resolv.conf

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oxygen_wobble

Member

Registered: 2012-05-20

Posts: 128

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

Hmm not much difference regarding abovementioned commands ...

192.168.1.1 dev wlp3s0 lladdr 9c:80:df:7e:5c:f5 REACHABLE

becomes

192.168.1.1 dev wlp3s0 lladdr 9c:80:df:7e:5c:f5 STALE

for 'ip n s' (some seconds after the problem occurs)

and 'route' (or 'netstat -r') just gets stuck and displays nothing.

Maybe this dmesg output is interesting:

[18890.051646] wlp3s0: AP 9c:80:df:7e:5c:f6 changed bandwidth, new config is 2472 MHz, width 2 (2462/0 MHz)

EDIT: I've read that there were some bug reports regarding iwlwifi and bandwidth change, but as far as i've understood, those have been fixed ?

Last edited by oxygen_wobble (2015-05-16 21:51:42)

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

See ideas in older thread.

oxygen_wobble

Member

Registered: 2012-05-20

Posts: 128

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

See ideas in older thread.

Hmm, the problem seems to be different there, as the connection just gets slow, but in my case, it's not working at all ... as i said, i can't even ping the router by ip,
all routes are cut ...

I've also tried repairing the connection from my side, restarting everything, disconnect, reconnect, rebooting my laptop ... to no avail.
The only way to make it work again seems to be restarting the router (to the chagrin of my flatmates ...)

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

Your "previous laptop (arch)" - is that up-to-date with packages? Maybe it's a recent version of e.g. wpa_supplicant which creates the problem.

Re "all routes are cut" - have you run "route" or "ip route" and checked the output?

oxygen_wobble

Member

Registered: 2012-05-20

Posts: 128

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

Re "all routes are cut" - have you run "route" or "ip route" and checked the output?

Jep, did that ... no output at all (it got stuck, more or less ....)

Currently trying to use a fixed channel setting on my router, maybe that helps ...

oxygen_wobble

Member

Registered: 2012-05-20

Posts: 128

Re: WLAN (iwlwifi) - no connection/route after bandwidth change ?

Hmm now i've disabled 802.11n on my router and switched to b/g mode ... seems to have solved the problem for now, but i wonder why it's not possible to use n or mixed mode ???