Randomly Need to disable and re enable Networking to Work

[wrender]

I have found that randomly I need to toggle enable networking on and off because my connection to my router goes zombie. This is a recent problem. I guess some update has a regression in it. I can accelerate the problem by trying to use ktorrent. With general web browsing it doesn't seem to be a problem except once and a while.

If I dual boot up into windows no problems with anything even torrent use. My phone has no problems either.

[SteveRiley]

Anything in your syslog when the problem occurs? Perhaps you're losing a DHCP lease. Can you ping the IP address of your default gateway?

[wrender]

How do I check those?

[SteveRiley]

Next time your connection goes down, immediately do the following.

1. Open a Konsole and run route. Example:

steve@t520:~$ [B]route[/B]
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         [B][COLOR="#0000FF"]192.168.0.1[/COLOR][/B]     0.0.0.0         UG    0      0        0 eth0
10.0.0.0        10.18.5.182     255.0.0.0       UG    1      0        0 tun0
172.16.40.0     *               255.255.255.0   U     0      0        0 vmnet1
172.16.70.0     *               255.255.255.0   U     0      0        0 vmnet8
192.168.0.0     *               255.255.255.0   U     1      0        0 eth0
192.168.0.0     *               255.255.255.0   U     9      0        0 wlan0
192.168.0.1     *               255.255.255.255 UH    1      0        0 eth0
sslvpn.riverbed 192.168.0.1     255.255.255.255 UGH   1      0        0 eth0

2. See the (blue) IP address in the "Gateway" column that corresponds to the row with the word "default"? Ping that IP address. Example:

steve@t520:~$ [B]ping 192.168.0.1[/B]
PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.
64 bytes from 192.168.0.1: icmp_req=1 ttl=64 time=0.541 ms
64 bytes from 192.168.0.1: icmp_req=2 ttl=64 time=0.598 ms
64 bytes from 192.168.0.1: icmp_req=3 ttl=64 time=0.592 ms
64 bytes from 192.168.0.1: icmp_req=4 ttl=64 time=0.504 ms
64 bytes from 192.168.0.1: icmp_req=5 ttl=64 time=0.606 ms
^C
--- 192.168.0.1 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4000ms
rtt min/avg/max/mdev = 0.504/0.568/0.606/0.042 ms

Press Ctrl+C to stop the pinging.

3. Reset your connection, then go to http://paste.ubuntu.com/, copy the contents of the file /var/log/syslog into the window, and report back here with the URL of the pasted file.

[wrender]

Here is the Url:

http://paste.ubuntu.com/1638447/

[wrender]

Sorry it took so long here is the precursor to the var file...



Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.1 0.0.0.0 UG 0 0 0 wlan0
link-local * 255.255.0.0 U 1000 0 0 wlan0
192.168.1.0 * 255.255.255.0 U 9 0 0 wlan0




PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
^C
--- 192.168.1.1 ping statistics ---
9 packets transmitted, 0 received, 100% packet loss, time 27083ms

[GreyGeek]

I had a similar problem with a new wifi device I purchased. It offered 11n but the wifi chip in my laptop wouldn't work well with it.

Did you put your wifi connection into a 'high bandwidth' mode, presumably 802.11n? If so, try resetting your wireless device to 802.11g by entering 192.168.1.1 into your browser location bar, and giving your credentials. Then browse to the bandwidth settings of the wireless device and check them. If you reset them to 11g then save and reboot the wireless device, and log back into your wireless.

[wrender]

I haven't put anything or done anything. I just noticed this problem creep in over the last few weeks.


ps. The router is set to mixed channels.

[GreyGeek]

Ah. Try settng it to 11g (54Mb max) and see if that helps.

[wrender]

After a long duration of degradation it seems it was one of the antenna on the wireless tower I have is fuzzed. So it was not Kubuntu...it was a home power wifi antenna breakage in case anyone was curious.

[dmeyer]

Ah. Try settng it to 11g (54Mb max) and see if that helps.

The issue is almost never on the router side unless other clients get the issue. More often than enough its on the pc side. Usually disabling(if enabled)/enabling(if disabled) 802.11n. I know this trick works on quite a few intel wifi chipsets.

[sithlord48]

i've had this every maybe 100 boots with my wired lan but have only ever seen it happen on my desktop never on any of the dozen other machine i use w/ kubuntu on it.

[GreyGeek]

I had a recurrence of the need to stop and restart the network even though the network manager does not indicate any problems. Pinging a host in a console shows that the DNS is not working, but my browser does not show any indication of a broken network until I try to refresh or call a different page. Then it hangs, but doesn't give any errors.

Recently I've been putting my laptop to sleep instead of shutting it down, so that if during the night I have a flash of insight or remember that I forgot to check something I could just hit the power button and within 10 or 15 seconds I had a working desktop. What I've discovered is this: If I start from a cold boot my network connection is constant and stable. If I return from a sleep mode the network problem appears. The more times I put my desktop to sleep and then wake it up the shorter the time the network connection stays up. I have to uncheck the checkbox "Enable Networking", wait a few seconds and re-enable it. That gets the network connection going again for awhile .... sometimes a few seconds, sometimes a few minutes, but never for very long. I also noticed that if I wait and do nothing, usually for about 60 seconds, the connection starts up on its own again. This occurs on both a wifi and eth connection, and even when both are connected at the same time! It's the protocol that is shutting down and restarting on its own. Syslog show no error messages or other indications. The disconnection line has the status indicator "Managed".

It's similar to this bug:
https://bugs.launchpad.net/ubuntu/+s...ux/+bug/945379
Yesterday I found a launchpad bug report relating the bug to a kernel recursion in kernels newer than 3.1 but I can't find it right now.

So, until a fix comes down the pipe I will be shutting my computer off at night instead of putting it to sleep.

[GreyGeek]

So, until a fix comes down the pipe I will be shutting my computer off at night instead of putting it to sleep.

About a week later I can report that since I stopped using the sleep mode my connection problems have disappeared.

[Snowhog]

See No wireless connections after sleep/suspend over on Ubuntu Forums. It has a 'solution' that you might want to explore.