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Thread: DNS resolution randomly stops working

  1. #21

    Default Re: DNS resolution randomly stops working

    Quote Originally Posted by deano_ferrari View Post
    Hmmm....a power management issue perhaps?

    https://askubuntu.com/questions/1030...untu-18-04-lts
    I will try it to see if that resolves the problem. However, I've done some more troubleshooting and think this may be a firmware issue or a problem with the driver. I have a qualcomm atheros QCA6174 card, just like one of the posters in that thread. I seem to have better luck with the 5GHz connection rather than the 2.4, as I have been connected for over an hour in that band and have yet to have the problem reappear. I also booted up windows for a while and had the exact same problem with the 2.4 band as I'm having on linux. So, I'm starting to think this is a vendor driver problem. Maybe I'll just swap it out for an intel card so I don't have to deal with it.

  2. #22
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    Default Re: DNS resolution randomly stops working

    Quote Originally Posted by z2 View Post
    I will try it to see if that resolves the problem. However, I've done some more troubleshooting and think this may be a firmware issue or a problem with the driver. I have a qualcomm atheros QCA6174 card, just like one of the posters in that thread. I seem to have better luck with the 5GHz connection rather than the 2.4, as I have been connected for over an hour in that band and have yet to have the problem reappear. I also booted up windows for a while and had the exact same problem with the 2.4 band as I'm having on linux. So, I'm starting to think this is a vendor driver problem. Maybe I'll just swap it out for an intel card so I don't have to deal with it.
    This reads like progress. We look forward to a further update.
    openSUSE Leap 15.0; KDE Plasma 5

  3. #23
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    Default Re: DNS resolution randomly stops working

    Quote Originally Posted by z2 View Post
    Here is the output from the NM logs for this last time I lost connectivity. It looks like the connection is timing out after about 13 minutes, which seems to be approximately how long this takes to occur every time. There are some dhcp6 time out errors, but that's normal from what I understand since IPv6 addresses are not usually assigned via dhcp (correct me if I'm wrong). But, 13 minutes after connecting I just get a timeout message, and that's when I lose DNS. I can still ping IPv4 addresses however, even after the timeout error, and it generates no new logs. Any idea why the connection would just timeout?
    A working connection has both dhcp4 and dhcp6:

    Code:
    erlangen:~ # journalctl -b -u NetworkManager|grep dhcp
    Jan 09 08:07:12 erlangen NetworkManager[3651]: <info>  [1547017632.3379] dhcp-init: Using DHCP client 'dhclient'
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6006] dhcp4 (wlp3s0): activation: beginning transaction (timeout in 45 seconds)
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6025] dhcp4 (wlp3s0): dhclient started with pid 3737
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6614] dhcp4 (wlp3s0):   address 192.168.178.29
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6615] dhcp4 (wlp3s0):   plen 24 (255.255.255.0)
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6615] dhcp4 (wlp3s0):   gateway 192.168.178.1
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6616] dhcp4 (wlp3s0):   lease time 864000
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6616] dhcp4 (wlp3s0):   nameserver '192.168.178.1'
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6617] dhcp4 (wlp3s0):   domain name 'fritz.box'
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6617] dhcp4 (wlp3s0): state changed unknown -> bound
    Jan 09 08:07:16 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017636.8113] dhcp6 (wlp3s0): activation: beginning transaction (timeout in 45 seconds)
    Jan 09 08:07:16 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017636.8137] dhcp6 (wlp3s0): dhclient started with pid 4026
    Jan 09 08:07:17 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017637.4228] dhcp6 (wlp3s0):   nameserver 'fd00::a96:d7ff:xxxx:xxxx'
    Jan 09 08:07:17 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017637.4229] dhcp6 (wlp3s0): state changed unknown -> bound
    Jan 09 08:07:17 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017637.4287] dhcp6 (wlp3s0): client pid 4026 exited with status 0
    Jan 09 08:07:17 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017637.4288] dhcp6 (wlp3s0): state changed bound -> done
    erlangen:~ #
    You may want to check:

    Code:
    erlangen:~ # grep -v \# /etc/resolv.conf
    search fritz.box
    nameserver 192.168.178.1
    nameserver fd00::a96:d7ff:xxxx:xxxx
    erlangen:~ #
    Code:
    erlangen:~ # journalctl -b -u NetworkManager|grep policy
    Jan 09 08:07:13 erlangen NetworkManager[3651]: <info>  [1547017633.6202] policy: auto-activating connection 'FRITZ!Box Karl Mistelberger' (036bfd93-ed1b-452e-b982-2939fc8811f3)
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6777] policy: set 'FRITZ!Box Karl Mistelberger' (wlp3s0) as default for IPv4 routing and DNS
    Jan 09 08:07:14 erlangen NetworkManager[3651]: <info>  [1547017634.6780] policy: set-hostname: set hostname to 'erlangen.fritz.box' (from system configuration)
    Jan 09 08:07:16 erlangen.fritz.box NetworkManager[3651]: <info>  [1547017636.8159] policy: set 'FRITZ!Box Karl Mistelberger' (wlp3s0) as default for IPv6 routing and DNS
    erlangen:~ #
    AMD Athlon 4850e (2009), openSUSE 13.1, KDE 4, Intel i3-4130 (2014), i7-6700K (2016), i5-8250U (2018), openSUSE Tumbleweed, KDE Plasma 5

  4. #24

    Default Re: DNS resolution randomly stops working

    I think I resolved this problem. After poking around in my router for a while I noticed that I had the bandwidth for the 2.4 set to 40MHz. This was done previously to get an older wifi card to connect at proper speeds, which it was unable to do with the 20MHz bandwidth. However, after discovering this and doing some online searching, it appears that 802.11ac cards do not function well with a large bandwidth set on the AP. 40MHz for 2.4 or 80MHz for 5 will evidently cause random connection or resolution problems. This does not seem to affect older wifi cards as I have a couple older laptops that I tested this on, and they all worked fine with the larger bandwidth (802.11n). After changing the AP bandwidth back to "auto", my connection problems disappeared. So, all seems well now.

  5. #25
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    Default Re: DNS resolution randomly stops working

    Thanks for reporting back here with your progress.
    openSUSE Leap 15.0; KDE Plasma 5

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