Wireless issue - cannot establish new connections suddenly

Discussion in 'Networking and Computer Security' started by NeloForster, Apr 12, 2009.

  1. NeloForster

    NeloForster Source of Exyphetadolamin

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    Hi all,

    I used to post on these boards and do my best to help out with hardware issues... and now hopefully you guys can help me out with a very strange issue I've been encountering recently :) I'll try and fill you in with as much information as possible.

    Okay, so here's the specs:

    Windows XP SP2
    Intel Core2Duo E6600 @ stock (2.4ghz)
    2 GB Corsair XMS PC6400 800mhz RAM
    Nvidia Geforce 7900GTX 512mb (by PNY)
    DFI INF 975X motherboard
    2x Seagate HDD's (160gb and 320gb)

    To connect to the internet wirelessly, I am using:

    Freedom2Surf 8Mbit DSL connection through a British Telecom line.
    Buffalo Wireless-G USB 2.0 adapter - Model: WLI-U2-KG54L
    Buffalo Wireless-G High Speed ADSL2+ Modem Router - Model: WBMR-G125

    Encryption is WEP 128. 100% wireless signal. 54Mbps connection speed between my wireless adapter and my router.

    The problem:

    - About a month ago, my internet connectivity seemed to drop. I was still connected to my router wirelessly, but whenever I tried to load a webpage in a browser (tried Firefox, Opera, IE...) it would bring up a "page cannot be displayed" error.

    - Existing connections remained established and fine. I could chat on MSN, I could play the online game I had running.

    - I connected to my router via ethernet cable while this was happening, and managed to regain the ability to establish new connections. I could browse again perfectly.

    - I removed the ethernet cable, and whilst my existing connections were still fine, new ones could not be established again.

    - This happens regardless of whether I have many or few existing connections.

    - Restarting my router does not fix this.

    - Removing my wireless adapter and plugging it back in again does not fix this.

    - Refreshing my wireless connection to the router does not fix this.

    - I cannot ping any domains in command prompt.

    - My housemate connects to the same router wirelessly and does not share the same problem.

    - This has NEVER happened until about 1 month ago. I have used the same copy of XP for about 3 years and never experienced this.

    - There are no programs, or modifications installed which I had not installed in the past, when all was working perfectly.

    - Restating my PC fixes the problem, but it will eventually begin happening again within 48 hours.

    Measures I have taken to fix this -

    - I bought a new router (old one was a cheap Edimax one) - but the problem persists

    - I have done a full virus scan, and found nothing.

    - I have reformatted my HDD's and reinstalled Windows, but it still happens.

    - I have updated the driver for my wireless adapter with the ones from Buffalo's official site. This has not helped.

    - I have reinstalled the client for my wireless adapter using the installer from Buffalo's official site, but this has not helped either.

    - I have tried disabling my motherboard's network card in case it happened to be interfering, but this has not made a difference.

    - I have checked Windows Event Viewer, which doesn't give anything away. Only reports of devices functioning correctly (suuure!)


    I am quite baffled by this... I have concluded it may be something to do with my wireless adapter itself (since everything works perfectly when connected via ethernet) but as I'm no budding expert at networking, I would appreciate any help or suggestions.

    I hope the information above helps you understand the situation, but let me know if you have any questions.

    Thanks in advance!

    Nelo
     
  2. donkey42

    donkey42 plank

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    i'm no expert in networking, but i'll give it a shot, it seems that DHCP is occasionally dropping the ball (working intermittently)

    assuming you have DHCP server enabled in the router

    DHCP actually assigns IP's to devices on your network enabling devices to function correctly
    first enter the web config of your router and backup your settings

    then try powering everything off & reset router to manufactures defaults (press reset button for about 30 seconds) enter web config again and enter DSL stuff if it works load your backed up settings and retest it, if it works :good:, if not one of your settings is wrong, probably DHCP
     
  3. Anti-Trend

    Anti-Trend Nonconformist Geek Staff Member

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    It's not a DHCP problem like Donkey suggests, or you wouldn't have an IP on the local box. In other words, you wouldn't be able to communicate with the router or the sites you already had a state with. If you're torrenting through the box, it could just be running out of firewall states for you; i.e. it's low on memory. Or, as I suspect is more likely, it could be a DNS problem. Are you using a different set of DNS servers than your housemate?

    If one or more of your DNS servers is unreachable, you won't even be able to lookup websites to see if they're reachable, so that makes troubleshooting by trying to connect to sites by name tricky. One thing you can do to test this is by trying to ping 4.2.2.2 while the connection is acting strangely. It's an easy IP to remember, and using IPs directly bypasses the use of DNS entirely.
     
  4. donkey42

    donkey42 plank

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    assuming AT (god) is correct (because i can't remember him being wrong)

    who's DNS servers are you using ? (primary & secondary)

    Edit: if my memory is correct (and it stupidly usually is) it could fix everything by flushing the local DNS cache
    Code:
    ipconfig /flushdns
    read this for an explanation
     
  5. NeloForster

    NeloForster Source of Exyphetadolamin

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    Hi guys,

    Many thanks for the suggestions.

    I have now added a new registry entry to set the max number of negative entries in the DNS cache to 0. I have also executed "ipconfig /flushdns" - so I'll see how that goes.

    However, if the problem does lie within the negative dns entries, wouldn't that mean I'd still be able to visit new sites I've never visited before? I ask this because the problem occurred within the first two hours of having a fresh XP install, and I tried visiting some sites I'd not yet visited since the fresh XP install - with no luck.

    What worries me most is that it has started happening so suddenly. Even after buying a new router and installing XP again, it's happening still.

    Also, I forgot to mention in my original post that if I were to sign out of MSN, I would not be able to sign back in again. Same goes for the online game (Warhammer Online) - plays perfectly fine, can interact with other players, but if I close the game I am unable to connect to it again.

    Anti-Trend - networking isn't really my strong point - how would I find out which DNS servers myself and my housemate are using? I'd always assumed our ISP took care of that kind of thing.

    Thanks for the help so far guys - any other ideas would be much appreciated too.

    Nelo
     
  6. donkey42

    donkey42 plank

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    yes, because the DNS resolve domains recursively (e.g. DNS Recurser asks the root nameserver "where's example.com "try and receives a reply, try x.x.x.21" , so in tries x.x.x.21 and asks where's example.com and it receives a reply of "try x.x.x.43 so retries again with x.x.x.43 and receives reply "it's at x.x.x.88)

    well that the theory

    Edit: still can't believe I put that :doh:

    TCP/IP properties in control panel & networking networking tab & choose TCP/IP v6 or v4
    it should be fine

    Source
     
  7. NeloForster

    NeloForster Source of Exyphetadolamin

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    Ahoy,

    In that case, we're using the same DNS server.

    I'll try using a public DNS server for a while and see if that solves things. My housemate doesn't use the internet half as much as I do - so it might be that he's not experiencing the problems because he hasn't spent enough time browsing to experience them.

    One thing that concerns me though is that everything is okay if I hook my on-board network card to my router with an ethernet cable. Wouldn't DNS issues stop me from connecting to sites via that method too?

    Thinking on something I tried a few days ago... uninstalling my wireless network adapter and installing the drivers again whilst in the same Windows session actually solves the issue. As retarting my PC also solves the issue, do you reckon this could have something to do with the drivers or the device itself?

    Many thanks again!
     
  8. donkey42

    donkey42 plank

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    you will be, unless you change them, you will both be using you ISP's DNS, personally i use OpenDNS some pepole won't use them, but i think there better than my ISP's, a lot more reliable

    i've actually use OpenDNS for ages & to be honest i didn't know why, now i only partly understand[ot]i doubt myself regulerly[/ot]

    i don't understand, before or after updating XP's DNS nameserver & in your routers web config

    possably, i've never used wireless

    np, glad to help, even though i'm more suprised than anyone that i put what i did :doh:
     
  9. NeloForster

    NeloForster Source of Exyphetadolamin

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    What I mean is that whenever the problem occurs (It's intermittent (sp?)), if I connect to my router via ethernet cable, it's as if there are absolutely no problems whatsoever (wireless still running too) - but when I unplug the ethernet cable, it's back to the problems again (wireless alone) - All of this whilst in the same session of Windows.

    I'm implementing the ultimate test - I will borrow a friend's wireless card and see if things happen with that installed. My guess is that the problems won't happen... I hope. If thats the case, I guess I'll just buy a new network adapter and the problem will be solved.

    Problems like this one suck because you have to wait for them to happen again :/

    Well, I'll let you know the outcome of this one. Someone out there might be searching for an answer to the same problem... and there's nothing worse than finding threads without resolutions hehe.

    Good to see you're still on the boards Donkey. It was a couple of years ago when I used to post, and I remember we often helped the same people out.

    Thanks again :)
     
  10. donkey42

    donkey42 plank

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    well that will determine if the wireless dongle is the problem, but it still could be wireless AP, try switching channels

    keep me informed

    well "suck" wouldn't be my first choice of descriptive words
    thank you, didn't your alias used to be NeoFoster ?

    anyway i've being learning all the way
     
  11. Anti-Trend

    Anti-Trend Nonconformist Geek Staff Member

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    Is your wireless router a separate unit from the hardware you're using when you physically connect an Ethernet cable? In other words, are they two different pieces of hardware, or is wireless and ethernet both provided by the same router?
     
  12. NeloForster

    NeloForster Source of Exyphetadolamin

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    Hi Anti-Trend,

    Both wireless and ethernet are being provided by the same router.

    Donkey - I have tried changing channels previously, but this doesn't stop the problem from happening. I think there was another member called NeoFoster too... made me consider signing up again under a different name, but as I'd already generated thanks and posts on this account I decided to stick with it.

    I had a different router when this started happening, and hoped my new Buffalo one would solve the problems, but figures it's not the router after all. Restarting the router has absolutly no effect on solving the problem when it occurs.

    The only things that solve the issue are restarting my PC, or reinstalling the wireless adapter drivers - so it must be something PC-side. I have downloaded and tried different driver versions to no avail. Right now, it's looking extremely likely to be my wireless adapter that is the issue.

    I made two changes to my wireless adapter yesterday evening - I connected it to a USB extender cable so it is no longer plugged directly into a USB port. Can get pretty hot in my case, which has no back panel (oops) - so this will rule out overheating.

    [Edit]: Regarding the above - Actually, this all started happening after I installed a new heatsink and fan, which blows warm air toward the back panel. The problem hasn't happened since I've added the extender, moving it away from the heat.

    Secondly, I decided to have a gander at the drivers for the wireless adapter and saw it was set to work in B mode. I have now set it to G. That would've annoyed me a lot if I hadn't noticed that - connection is to be upgraded to 16Mbit soon - would've been an unwelcome bottleneck on speed :x:
     
  13. donkey42

    donkey42 plank

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    i may be misreading it, but, for ethernet connections to work they must be plugged in[ot]sorry to state the obvious[/ot]
     
  14. NeloForster

    NeloForster Source of Exyphetadolamin

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    Definitely misreading it :p

    Okay, lets say you're connected to a router wirelessly. Problems start occuring where you cannot establish any new connections, yet connections currently maintained are still fine (so if you were logged into MSN messenger, you'll still be logged into MSN messenger and also be able to chat with people).

    You then decide to connect your PC directly to the router using an ethernet cable (all of this while the wireless problems are happening). The problems you were having with being unable to establish new connections are gone - things work perfectly. You then decide to remove the ethernet cable to see if the wireless problems are still present. The problems come back immediately after removing the ethernet cable.

    So what I'm trying to say is that it's definitely a wireless issue.

    So far I haven't experienced the problem again since using the USB extension cable to move the wireless adapter away from the back of my case. But then, sometimes it doesn't happen for a few days... just hoping it won't happen again.
     
  15. donkey42

    donkey42 plank

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    that could explain the weird things if the CPU is a 2.4Ghz

    yes it is so the CPU is interfering with the wireless, problem solved
     
  16. NeloForster

    NeloForster Source of Exyphetadolamin

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    2.4ghz is the stock speed for all E6600's, and a quite a few other processors - If the CPU frequency somehow did have anything to do with the stability of wireless connections, almost everyone with a CPU operating at 2.4ghz would share the same problems. 2.4 - 2.5ghz is a common modern wireless frequency. As a CPU doesn't emit RF (instead, electrical voltage), its frequency cannot influence the stability of a wireless connection.
     
  17. Anti-Trend

    Anti-Trend Nonconformist Geek Staff Member

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    Yep, well said. I'm not exactly sure what's going on, but I'm pretty sure it's a problem somewhere on the network stack. This is especially because your existing states don't seem to die, you're simply unable to create new ones.

    When the symptoms appear, would it be possible to sniff traffic with Wireshark, zip and upload the pcap here?
     
  18. NeloForster

    NeloForster Source of Exyphetadolamin

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    Sure thing :)

    I'll upload it the moment I get a result.
     
  19. donkey42

    donkey42 plank

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    Source
     
  20. NeloForster

    NeloForster Source of Exyphetadolamin

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    That's only in reference to radio frequency radiation bands. Whilst Hertz are indeed used to measure radio frequency, Hertz is just the same measurement name for a different thing when it comes to CPU's.
     

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