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Update:

Sometimes when my connection dies, my computer does a slight "hardware freeze." The sound jitters as though a BSOD is about to happen, mouse freezes, video freezes. This happens for 1-2 seconds, then returns to normal, except for being disconnected from the internet.

The facts:

  • I am using a wireless NIC plugged into a PCI-E slot on my motherboard.
  • Sometimes I lose connection to the internet from my computer. There are usually no notifications for this other than I notice I am unable to browse the internet, or my dropbox green-checkbox-overlay disappears.
  • I retain LAN connectivity.
  • All other computers and devices retain internet connectivity.
  • Given steps 2 and 3, we can deduce that I am able to ping a web site from my computer by using my router's admin page. This is indeed the case.
  • I fix this issue by disabling and re-enabling my adapter (Windows 7). I do not wait after disabling my adapter; I immediately re-enable it. I do nothing else to the network at all.

Some thoughts:

  • If I needed to check DHCP settings, or lease time, or any of that, why would I retain LAN connectivity?
  • What is it that the NIC does upon being re-enabled that restores internet connectivity? If it somehow "refreshes" my NIC's IP, that would imply that it somehow got "stale" previously. Yet even in this stale state, I retain LAN connectivity! How/why? What is the core issue?
  • Better yet: could someone explain clearly and simply (my networking knowledge is very limited) how this could be anything other than a driver issue?
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I have a similar problem (Realtek wired NIC), except I only lose my internet connectivity when I download/upload a file at full bandwidth. Eg. Uploading a video to youtube makes me/other computers on my LAN unable to load any other sites (even though my LAN is still connected and I can access router page) until the upload is complete. Hoping any answer to you problem will be applicable to me too :) –  evol Oct 18 '10 at 1:49
    
@evol your problem is simply you don't have enough bandwidth from your ISP. Call them for more bandwidth if you are wishing to get around this issue. –  KronoS Oct 18 '10 at 4:51
1  
It's akso possible that this is an issue with the router, I had a D-Link 405g (I think) where the router would lose internet connectivity because it's internal state (ARP entry for the modem) would frequently become corrupted –  Crippledsmurf Oct 18 '10 at 5:09
    
@Crippledsmurf same happens occasionally on my Buffalo WHR-G300N, only booting the router helps. –  onik Oct 21 '10 at 5:17
    
Sounds a lot like you may have IP Address problems. Did you enable DHCP?' –  digitxp Oct 24 '10 at 14:38

3 Answers 3

You have not described how you get things back to normal. I suppose you just reboot everything?
Some things to try when this happens:

  1. Reboot the router but not the computer. If this fixes the problem, then the cause is with the router.
  2. Reboot the computer but not the router. If this fixes the problem, then the cause is with the computer or with its lease with the router.
  3. Enter on your computer ipconfig /flushdns. If things improve, then this is a DNS problem.
  4. Enter on your computer ipconfig /release followed by ipconfig /renew. If things improve, then this is a router configuration problem concerning the lease time of your TCP/IP address.

This check-list is not exhaustive, but it's maybe a start at analyzing where the problem is. Just remember to issue these commands from a Command Prompt that is Run as Administrator.

I hope you are using the drivers from May 2010.

Otherwise, as this happens with two routers, and only the external connection is broken, this could point to a problem with your ISP. I suggest you get in touch with their Support (and hope that they tell you the truth).

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Ack--let me edit the question with my temporary fix. –  Sam Pearson Oct 21 '10 at 6:55
    
Re-enabling the NIC might point to problems with the lease time. I couldn't find any info on it, so suggest you try going into the router configuration and search. –  harrymc Oct 21 '10 at 13:57
    
What happens when you try the above, and especially the 4th point ? –  harrymc Oct 22 '10 at 19:08
    
I'll try it out when I get home. I checked the lease time in my router's DHCP config page; it's 48 hours. –  Sam Pearson Oct 22 '10 at 23:09
    
I added some more possibilities. –  harrymc Oct 24 '10 at 14:22

If disabling and re-enabling the connection fixes the issue it is either: a) busted driver - fix is an update from vendor when they sort it out - i had a broadcomm that did this - windows driver update/PC manufacturer update didn't do it - i had to go directly to broadcomm b)someone is deauthing you and disable/enable causes it to reset - fix is to look at a network traffic dump and block the MAC of the offending wireless device

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If someone is deauthing me, how am I nevertheless able to connect up to the router's admin page? –  Sam Pearson Oct 26 '10 at 19:56
    
good point...looks like a busted driver or crappy firmware on the router...i once had an instance where a router and a surfboard had a problem that related to mtu. that's usually outside of scope though –  hbdgaf Oct 27 '10 at 3:10
    
Yep, looking to be either a driver issue or a firmware issue. Gonna try updating to DD-WRT to see if that fixes it. –  Sam Pearson Oct 28 '10 at 1:22
    
i would try openwrt before ddwrt. it's really just a fork that only distributes some binary components....of course i am an opensource freak so. just my 2 cents –  hbdgaf Oct 30 '10 at 14:15

This can be caused by many things. Some things to think about:
do you get the same problem when connecting to other wireless netowrks?
how far are you from your router and what is in between the router and your computer?
do you get the same problem when connecting to this router wirelessly with other computers or with another wireless device on the same computer?
do you have this problem in safe mode with networking enabled?
how many other devices are connected at the same time?
is your router properly secured?

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