Ubuntu Networking :: How To Diagnose Intermittent Wireless Connectivity
Jan 16, 2011
Just recently I've been having strange connectivity problems with my wireless network. The connection has previously worked fine and haven't had any problems with it. I haven't installed anything that would have affect it as far as I know. how do I go about testing the network to see where the problem lies? I'm running Ubuntu 10.10 with a Netgear WG111v2 wireless adapter and my guess is it is some strange configuration problem or a rogue application is eating up packets because the system works fine when I boot it up into Windows.
When I try to ping my router I'll usually get something like 98% packet loss. However in the output below, the network sprang to life half way through my pings so it went up to 63%. What other tools can I try to find out what's going on?
Code:
alex@obsidian:~/dev $ ifconfig
eth0 Link encap:Ethernet HWaddr 00:1a:4d:4e:03:3f
UP BROADCAST MULTICAST MTU:1500 Metric:1
I have a Huawei E 1550 USB stick modem and I'm trying to consistently get it working with Ubuntu 10.4. Using usb_modeswitch and wvdial I've got the device recognized as both a modem and disk drive and it seems to be working okay. wvdial usually is able to find the modem and connect and I can get online no problem. That's the good part.
However, after some amount of time (sometimes just a few minutes, sometimes hours, but it always eventually happens) the modem stops working and gets into a state where when I run wvdial it keeps looping and failing with:
Code:
ATDT*99# NO CARRIER --> No Carrier! Trying again. --> Sending: ATDT*99#
[code].....
Interestingly enough, when it's in this state I am still able to access the modem, and via AT commands am able to see that it has signal, can make phone calls, and can send SMS messages! It just can't seem to dial a data connection. Now, unplugging and plugging the modem back in almost always seems to solve this problem, only for it to fail randomly at some undetermined point in the future.
Why can't I just keep unplugging and replugging the modem, you ask? Because the computers (yes there are currently 9 computers and modems I need this to work on) are being deployed to clinics and offices in rural Africa where they will be locked in a box so they aren't stolen. I have pursued ways to shutdown power to the USB port in order to "fake" a hard pull of the cord in software, but haven't been successful so far. I've also tried reading as much as I can on the NO CARRIER response, but so far it's not turned anything up.
To be brief, I am having intermittent connectivity issues with a wired connection to a WRT54G2 router. I have no such issues if I am plugged straight into the modem. My wireless persists throughout the outages and they usually require me to restart the interface on my machine. I have used Wicd Network Manager and Ubuntu's out-of-the-box Network Manager.
hostname -rs Code: Linux 2.6.32-25-generic ifconfig eth0 .....
Wife's laptop has AR5001 Wireless Adapter laptop model is Toshiba Satellite A215
Problem : Wireless networking randomly loses connectivity and can not regain connectivity, the only apparent solution is a full power down , this is not even certain to work. The card works under Windows, she hates Windows. (I love her for this) I know it's not faulty hardware , because it will work for days on end under Windows without problems.
Things I've tried : madwifi drivers (any and all versions available) : These increase stability of the signal and seem to delay the inevitable however it still happens. When using these drivers the only option is to unload them modprobe -r then reboot then remove them again and re add them. It makes no sense why this works, and if I don't remove them prior to rebooting it will not work.
ATH5K drivers : These are pretty much junk, results are unpredictable at best, sometimes it will work perfectly for a few hours, sometimes it will not work at all. Nothing is repeatable, I can't seem to force whatever condition is causing this. rfkill does not show the wifi being blocked (hard or soft), unblocking it anyway does nothing, only way to make this work and it's iffy is to fully power down wait 5-10 minutes turn it back on and it MAY decide to work.
Firmware update : Updated the Toshiba BIOS to the latest version of the firmware 2.0 no joy here either. Same issue both sets of drivers.
Tried different distros and kernels : I've tried Mint 9, 10 ,11 ; Ubuntu 10.10, 10.04 , 9.10 and 11.04 (which is currently installed) , Fedora and OpenSUSE. All are giving the same problems. I have also tried a slew of different kernels no joy from any of them (I'm not at the computer with the issue now I will post exactly what kernel versions I've used when I have access to the machine).
Another useful bit of information, the hard switch to disable/enable wifi WILL disable it but turning it back on does absolutely nothing. The hotkey does nothing at all. The bios does not have an option to disable or enable the wireless card.
I will also post the typical lsmod , lspci , iwconfig all that good stuff when I get back to the computer in question. I'm probably just going to buy a PC card for it and give up on that one, but this is driving me insane and I would really like to see it resolved even if I do replace the hardware.
As promised the finished (pretty much finished) wireless script can be downloaded here the wireless_script is a diagnostic tool for wireless issues. It will return all relevant information to help diagnose a wireless connectivity problem, return connectivity stats and attempt to fix common problems such as blocks. It comes in cli - wireless_script_1.2.sh or gui - wireless_script_zenity_1.2.sh'
Let me know any issues you have with it. My contact details are in the readme.txt (also the wireless results.txt generated by running the script includes code tags for forums - so please copy and paste the whole document when pasting on forums to enable this function)
Using my usb mobile broadband dongle I am able to access the internet about 25% of the time. I am able to make a connection to the '3' wireless network 100% of the time, but often Mozilla and all other applications that rely on an internet connection do not recognise that this connection has been successfully established, and give me error messages claiming there is no internet connection.
I can't discern any pattern as to whether the connection will be recognised or not. When it isn't recognised, the only solution is to disconnect and reconnect to the network. Sometimes this works and sometimes it doesn't. Sometimes restarting the computer fixes the problem, and sometimes it doesn't. I also have access to a wireless network at uni. I have no problems using this network whatsoever. Housemates using the same dongle on Windows have no problems. I'm using an Acer Aspire one, the dongle is a Huawei e220, I'm running Ubuntu 9.10. I have only recently reinstalled the operating system and have not needed to mess around with any network settings to get the usb dongle to 'work' the way it is currently.
I have an old Tatung tablet pc, with touchscreen, stupid speakers and an atheros wifi card (AR5001X+). With XP, everything works reasonably well, and wifi connectivity is rock solid. I know I'm asking for trouble installing *nix on this machine, but if the wireless worked, I'd be happy. However... With an updated Lucid install, I can see and connect to open, WEP, and WPA(1/2/tkip/aes/whatever) networks. I get good speeds with every network I've tried, but after a minute or two, my connection speed drops to zero, only to recover after another few minutes. A few minutes later, the wireless dies again, then reconnects....
Both the router and the tablet show that I still have a connection, and the connection speed recorded by both does not change from the 'working' condition. I get nothing in the logs (router or tablet) and no indication (aside from transfers stalling) that there's any problem. The 'network history' part of Gnome system monitor shows the data rate dropping to zero, but a network monitor applet on the gnome panel shows transmissions and (later) recieves. Reported signal strength remains constant, and seems to have no bearing on the frequency or length of the dropouts.
I've tried the stock lucid drivers, the lucid wireless backports, and madwifi (currently on madwifi) with no change to symptoms. I did think that it may be to do with scanning for networks (iwevent showed completed scans as the dropouts ended) so I removed network manager and tried static configuration with /etc/network/interfaces . The problems persited (although iwevent is now silent) and I am now using Wicd with no change.
lscpi:
Code:
sudo lspci 00:00.0 Host bridge: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02) 00:00.1 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
[code]....
I see nothing toobad in these, so I ran a longer test - I bash'd a while loop to ping the router, run ifconfig and iwconfig, and spit the results into files. I concurrently ran a wireshark capture. All of these contain a lot of text/data, so I've attached them here. I can't see any connection between the output of ifconfig/iwconfig/wireshark while the ping drops, but I'm no expert.
I got a NetGear wireless router recently. Attached it to my Huawei (pardon the spelling) modem. I have a HP 540 laptop running Ubuntu 10.04 The wireless gets connected. But there's an exclamation mark almost all the time. Very frequently these days, the connection gets bogged down or websites just don't open at all. But the icon (with the exclamation mark) shows Active Connection. I don't know where to start looking for bugs. Seems odd. Wireless is connected, I can connect to sites, but there's the exclamation.. and sooner or later, connection goes off but the icon still stays the same with "active" label.
I just upgraded to Ubuntu 10.10 because I was facing internet problems with previous Ubuntu 9.04 after I upgraded it with downloaded software. And now, 10.10 connects to wireless, but shows web-page some-times and repeatedly disconnects. Earlier it wasn't reaching Internet at all. Some of the topics here helped a lot. But this intermittent internet seems not going anywhere. Wired Internet connects easily though.
I've tried :-
-disabling ipv6..... first in Firefox, then in Kernel also -Setting DNS.....System> Preferences> Network Connections -setting static Ip
I've been trying to use the wireless adapter that came shipped with my computer for a while now (it is NOT a USB adapter; it seems built into the computer). However, I can't seem to get it working.HP says that the driver is Lite-On USB Wireless 802.11 b/g Adaptor. I am currently connecting to the internet with my netgear USB adapter (I think the driver is something like prism_usb)
I am new to linux. I just installed linux on my PC and wanted to configure wireless network connections. I have entered SSID and mode is set to infrastructure. I don't know what is BSSID do I need to enter MAC address (of router?)?I need to connect to internet wireless can you please guide me ?
I have a Air-CB21AG-A-k9 cisco Card and trying to run it with Ubuntu 11.04. But this card doesnt seems to be plug n play device with ubuntu 11.04. As soon I inserted the card both the leds are flickering but no wireless conectivity.
I'm running Lucid Alpha 1. Installed it about two weeks ago. Until a few days ago, the wireless networking was the best I've witnessed on any o.s. However, after last Wednesday's updates, connectivity now lags about 10-30 seconds whenever I open any web-page or access the repositories via aptitude. Granted after it gets going, it's fine. I noticed this same behavior in 9.10. I tested my XP connection and found no problems. .
I recently formatted an old Dell D600 and installed 9.10 on a single partition. It connects to my Airport just fine hardwired, but I have had no success getting the IntelPro/Wireless 2200BG card to talk wireless. I've entered the SSID and WPA2 security ID with no success.
I just installed Ubuntu 10.10. I was using iBall N 150M USB adapter for internet connection with Windows XP. Let me explain about the present Windows connection :
I am using an Outdoor CPE Wimax. For mobility purpose I have connected this wimax to one LAN port of ADSL+ WiFi router ( Beetel 450 TC1 ). This ADSL+wifi router reset to Factosy settings and enabled DHCP. With this setting , I am perfectly able to connect my laptop to Internet.
When I connect my USB adapter to Ubuntu , intially it detected the signal and asked for credentials. I gave the same and network established. But I am not able to browse the net. If I give [URL]..., its going to the ADSL+Wifi's diagnosis page. With Windows , [URL]... was going to the Wimax modem. After 2-3 trial and error , now Ubuntu also not able to connect to the wifi network.
May I please have some help configuring wireless connectivity?I just moved and went from connecting to a LAN infrastructure to connecting with a wireless cable modem. The modem is dual-purpose, it has two ports, one for an Ethernet cable, and an access point for a wireless connection. The ISP is CableOne. My laptop, which I use most often, is wireless capable, and I want to use the wireless feature. The laptop is running Fedora 13 KDE, with a VirtualBox virtual drive running WinXP.
I have used NetworkManager to create a wireless connection and name it. I have also used WPA encryption for this because I don't want anybody else using my bandwidth. Moreover, I have tried no encryption and WEP, all to no avail.
The problem is I have a wireless Belkin router which I can connect to, but after being connected for a few minutes the net disappears (cuts from the router) and my laptop will have to reconnect again to the router for internet to work again. After a few minutes (or seconds in some cases) the connectivity loss will happen again over an over.
How to fix this problem or some things I can try, I've tried updating to two different firmwares, two different channels and resetting the router. The biggest problem I find is that this happens on both my laptop, another laptop in the house and also my tablet PC but doesn't happen on two other laptops in the house, I've also tested with windows 7 and Ubuntu with my laptop.
My laptop wireless card is Atheros AR9285 802.11b/g/n WiFi Adapter
I have just upgraded to 10.04 and can't get wireless connectivity because the STA driver for bcm4312 fails to activate. Does this sound familiar to anyone? I had had similar problems in 9.10 and tried to install bcmwl-kernel-source which apparently caused errors in the upgrade process. Not sure if this is part of the problem.
I got ubuntu working fine on my netbook and wanted to play around with opensuse. I have it installed and everything works fine except my wireless connection. I have updated everything since the installation through a wired connection, that didn't help. I have read the stickies, but to be honest, I'm so new to this stuff I'm kinda lost. So my wireless network has a WEP encryption and I have entered that password as a 64 HEX Key in the Wireless Manager widget. It connects to the network and says is labeled as active, however there is still the yellow exclamation shield next to the connection. Firefox and other apps don't have access to the internet.
Using a set of instruction given to me, I was able to set up a Macintosh system running Mac OS X to successfully connect to a virtual private network.I then tried to adapt those same instruction to configure a system running Fedora Linux 12 on an Intel Core2 Duo system.However when I try to connect using the NetworkManager Applet, I get an error that saying the VPN connection failed, with no clear indication of what the actual problem is.What can I do to troubleshoot this problem and find out why the connection is failing?
Installed openSUSE 11.3 over an existing 'very stable' 11.2 installation and started experiencing wireless connectivity issues immediately. Network Manager would show connected 100% - 92% but I would lose connectivity to mail, browser and messenger(s). This disconnect would last less than 30 secs but would occur every 2 to 4 minutes.
dmesg reported:
[ 3663.672098] iwl3945 0000:03:00.0: Failed to get channel info for channel 3 [1] [ 3664.101085] iwl3945 0000:03:00.0: Failed to get channel info for channel 3 [1] [ 3664.529050] iwl3945 0000:03:00.0: Failed to get channel info for channel 3 [1]
BTW Channel 3 is the channel my wifi is broadcasting on. I've tried other channels and other computers and it is only openSUSE 11.3 having an issue. I am also using WPA2. Modifying the Global Options in Network Settings from User Controlled with NetworkManager to Traditional Method with ifup seemed to stabilize most of the issues, but I do notice occasional drops. I've also switched from Network Manager to wicd to provide some UI while dealing with this issue. Since iwl3945 drivers are now in the kernel I don't know if I should try to revert to an older driver or if there is another issue.
I have an older Gateway with model number: 4024GZ, and I just installed Ubuntu on it and I am not able to connect to my home's wireless network. I am assuming that this is because of a driver issue, whether there is none or the old driver isn't compatible. So is there a website that I can go to to maybe find a driver that will work with both my wireless card and ubuntu? My wirless network adapter is internal and is a Broadcomm I believe. (btw I am a beginner here and if I have posted this in the wrong section,
My reinstalled OS Linux Lite ( version 1.0.9.E) connects fine with cable but Broadband BT hub does not support the protocol for wireless.Is there a Linux download which will solve this?
I recently installed Ubuntu on my MacBook and it's great. The only problem is the Internet speed... on Mac OS X it is much faster which doesn't surprise me because both have been optimized to run fast.
I was wondering if there was a driver, or similar, that would improve the speed for Ubuntu?
I'm having making network/internet connection with my laptop. I have:Toshiba 1415 S173laptop NetGear WG511T pcmcia card using madwifiNetGear WPNT511 pcmcia card using windows driver via ndiswrapperSlackware 12.2In both cases the card is recognized, and I can get a list of access points with iwlist.I can set the card to connect to the desired access point. I can use dhclient to get an ip address from the remote dhcp server. This works, the card is assigned a valid ip address on the desired network.Once I do this, however, I cannot access any network resources, no Internet, and no other devices on the network can see, ping, or access my laptop. It does this with with both cards, using madwifi or the windows driver via ndiswrapper.
Every so often while browsing, DSN fails. The thing is that if I DIG the address at the command prompt the site immediatly pops in in Firefox. what I should do to diagnose the problem.
I have been running 10.10 server with no GUI for a few months without issue. I decided to install ubuntu desktop (GUI), because I want to turn it into a media server, and I'm finding that my Internet browsing fails intermittently. i.e. I can get [URL] sometimes and sometimes not. I have tried traceroute and found that I do not reach my local router on addresses that fail, and yet I get a full trace on addresses that are ok. Ping tests too.I remember from some time ago that the GUI may cause a network problem but I'm not sure. By the way, other computers on the network can access this host through Samba so the NIC is working fine.
I've got UNE 10.10 installed on a Samsung N150 that uses the RTL8192E for wireless. When the wireless works then it generally works okay, but I'm having problems with reboots and long-running connections. This is different to the mass of posts (mainly from 2009) about the card not working at all, so I started a new thread.Basically, 90%+ of cold boots result in a successful wireless connection, with Network Manager remembering my WPA password.
When the wireless is up then it never obviously drops out, but I've got an app with a long-running connection that seems to disconnect itself occasionally. Looking at Wireshark then it appears that there are a number of retransmits, and a big batch just before it disconnects (which implies that the app is dropping its connection because it thinks the other end disappeared). Running the app on another machine with a different card but through the same release of Ubuntu and the app and the same router doesn't result in retries or drop-outs.On the times when a cold boot doesn't successfully reconnect then it asks for the WPA password, then continues trying, then asks for the WPA password again, then continues trying, then asks...and so on until I rmmod and modprobe the driver.
I originally had problems with the machine refusing to restore after a hibernate/suspend, but this was solved by a tip to rmmod the driver on hibernate/suspend and modprobe it on restore.The wireless will now work okay on some restores, but is more likely to repeat the behaviour described above for the failed cold boot.
Attached is a file with some snippets from dmesg around the time of the wireless failure, and the log of what it does after a remove and re-add for comparison of the "correct" messages.
I have a server with two ethernet ports. I configured eth0 to be static, set at 10.1.10.148. I plugged in another router into the other ethernet port in order to configure that router. I configured eth1 to use dhcp. Using /etc/network/interfaces rather than gnome network manager. When I did this, I lost internet connectivity (internet routes through eth0 of course)
- Why did I lose internet connectivity?
In order to recover internet activity, I had to disconnect the new router on eth1 of course, and do sudo ifdown eth1. That wasn't enough however. After rebooting numerous times and pulling out my hair, I finally tried configuring eth0 as dhcp, rather than static, and this fixed the problem.
- Why didn't sudo ifdown eth1 solve the problem? What information was saved between reboots that somehow remembered that I plugged in the new router? Because my thinking was if /etc/network/interfaces was identical, and the network topology was identical, after a reboot everything should be restored, but it wasn't.
