Re: Sporadic DNS failure

On 2024-03-14 21:13, Sreenath Battalahalli wrote:
> Hi Chris,
> 
> Thanks for your message.
> The wifi continues to be associated with access point, and I can ping 1.1.11 
> as well.
> My USB wifi interface is rtwn(earlier urtwn)
> 
> It is just that DNS queries fail, even when 1.1.1.1 is accessible, at least 
> to ping.
> 
> Is it possible that UDP communication is failing?
> Is there any log information that can shed more light on the issue?
If ping(8) is your only failure. I'd not be surprised that those addresses 
you're pinging
drop ICMP packets. As they're frequently used in attacks. The FreeBSD ping(8) 
used to also
have an alternate (UDP?) option. My advice; try (pinging/tracerouting) 
additional hosts
before concluding it's your DNS/network. Perl.com, fe; doesn't drop ICMP 
echo, neither does
microsoft.com. If you get a response. It's probably just the hosts you've 
been using. Not
your DNS/Net.

--Chris
> 
> thanks,
> Sreenath
> 
>      On Friday, March 15, 2024 at 12:48:47 AM GMT+5:30, Chris
> <bsd-lists@bsdforge.com> wrote:
> 
>  On 2024-03-14 00:12, Sreenath Battalahalli wrote:
>> Hi,
>> 
>> I have been using freebsd as my primary OS on my ACER laptop for many years
>> now.
>> My laptop has 802.11AC card for which there is no kernel driver available I
>> am I
>> use a USB wifi adapter to access the wifi router.
>> 
>> I am having sporadic DNS failures .
>> 
>> After reboot, everything works fine but after some time (30 minutes to a
>> couple of
>> hours), Internet
>> connections start to fail.
>> 
>> When this happens, I am able to ping 1.1.1.1, my DNS server.
>> 
>> However,
>> # drill yahoo.com (or any other name) fails with following error:
>> 
>> Error: error sending query: Could not send or receive, because of network
>> error
>> 
>> Other devices connected to same Wifi router continue to work fine.
>> 
>> I ran drill under truss and it appears after sendto to 1.1.1.1, no response
>> comes.
>> 
>> After this error occurs, it stays like that for many some time (20-30
>> minutes) and
>> sometimes it gets resolved by itself.
>> 
>> 
>> #uname -a
>> FreeBSD bsd12 13.0-RELEASE-p13 FreeBSD 13.0-RELEASE-p13 #0: Mon Aug 29
>> 19:52:47
>> UTC 2022    root@amd64-builder.d
>> aemonology.net:/usr/obj/usr/src/amd64.amd64/sys
>> /GENERIC  amd64
>> 
>> Can someone please help me debug this problem?
> I'm going to suggest that this might be a symptom of your usb port/hub
> hanging-up/
> disconnecting due to inactivity. Your BIOS setup may have a setting
> associated
> with that. OTOH I don't know what NIC driver you're using for your USB
> network
> adapter. When you discover you can't perform DNS lookups, are you still
> associated?
> eg; does the output of ifconfig still show associated? What are the settings
> in rc.conf(5) related to your network setup?
>> 
>> Thanks,
>> Sreenath
> 
> HTH
> 
> --Chris