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I'm trying to narrow in on why one specific PC I have cannot connect to the Internet, nor even ping the router it is connected to, but is fine on other networks, and other devices are fine on the router.

It is specifically this PC with this router, as far as I can tell.

It had been working previously, I cannot tell what has changed - as far as I know, nothing.

Problem

  • PC is dual-boot Windows and Linux.
  • Under Linux, the wifi connection to the BT Router shows as 84% strength, and it gets an IP via DHCP (confirmed by checking from another laptop)
  • Under Windows, the network connection also is strong from the wifi point of view, but shows "No Internet"
  • Under both OSes, pinging the router's IP itself results in 100% packet loss *
  • From other laptops, pinging the router returns pings and 0% packet loss
  • I can connect this same problem PC to my phone's wifi hotspot and it connects and routes fine, can ping 8.8.8.8 without issue

Attempted further troubleshooting

  • Tried flushing DNS and network cache in Windows, no effect
  • Under Linux and Windows, tried using a static IP with the expected configuration (router IP, DNS mask, IP on correct subnet, chosen static IP known to be unused), matched against a working laptop - no effect, still cannot ping router
  • tried moving router closer to desktop PC, no effect (really does not seem to be a signal thing)
  • ensured router was not configured to block any devices
  • restarted the router
  • reset router to factory defaults, tried using default SSID and password

* Sometimes it is between 70% and 100%, more frequently 100% loss. I sometimes also get a lot of duplicate packets back - one attempt recently gave me:

--- 8.8.8.8 ping statistics ---
10 packets transmitted, 2 received, +65 duplicates, 80% packet loss, time 9236ms
rtt min/avg/max/mdev = 852.490/1313.819/2760.262/301.680 ms, pipe 3

Any suggestions on troubleshooting this would be helpful, either Windows or Linux commands ; any suggestions on what configurations to look at/read up on welcome.

I don't have the cabling to test ethernet to the router from the desktop at the moment.

Update

It seems the netwokring does work for a few seconds after joining the router (successful pings), and then after a bit, it starts failing again. I mistakenly thought LiveUSB was working but it isn't - rather, it is presenting the same symptoms as the installed OS, that is, for a few seconds networking is fine.... and then it starts failing.

Not the case with my tether.

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  • Can your router be configured to deny connection to specific MAC addresses? If so, check to see if the problem laptop's MAC address has been (inadvertently?) denied.
    – Jeff Zeitlin
    Commented Jan 24, 2021 at 18:02
  • Already checked that, it is not set up to deny anything.
    – tk-noodle
    Commented Jan 24, 2021 at 18:21
  • Guess: Something goes wrong with the combination of your PCs Wifi hardware and your routers Wifi hardware. Try iw phy and iw dev wlan0 scan dump` as root to see which capabilities your Wifi hardware claims to support, and which capabilities the router claims to support, possibly one of those doesn't work correctly. Also compare with other PCs (if running Linux) for which the router works.
    – dirkt
    Commented Jan 24, 2021 at 19:09
  • Can the problem computer connect to other wifi networks (e.g., public hotspots at McDonald's or Starbuck's)?
    – Jeff Zeitlin
    Commented Jan 25, 2021 at 12:08
  • Yes it can, my phone wifi hotspot works fine for it
    – tk-noodle
    Commented Jan 26, 2021 at 11:35

2 Answers 2

Reset to default
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Do you have wifi drivers installed in windows? See here: https://www.windowscentral.com/how-check-device-driver-version-windows-10

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  • It used to work fine and, yes, I had indeed installed the wifi drivers.
    – tk-noodle
    Commented Jan 25, 2021 at 16:25
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Since you've tried a new static IP, try a new MAC.

On Windows, go to Device Manager, find your network card, go into its Properties, and in the Advanced tab change the value of Network Address.

On Linux you may try one of those methods: https://ostechnix.com/change-mac-address-linux/

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  • Finally gotten round to this. Alas, did not help. Changed MAC, restarted networking, received new address, but still same symptoms....
    – tk-noodle
    Commented Feb 6, 2021 at 15:33

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