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Intermittent DNS failures

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Apologies again, I'm not reading you posts closely enough. Too many very similar filenames.

What's the output of:
Code:
cat /etc/resolv.conf

grep -i mypc /var/lib/misc/dnsmasq.leases
Code:
admin@RT-AX86U-AR28:/jffs/scripts# cat /etc/resolv.conf
nameserver 127.0.0.1

Code:
admin@RT-AX86U-AR28:/jffs/scripts# grep -i myPC /var/lib/misc/dnsmasq.leases
30089 f7:a4:67:4d:5f:8a 192.168.1.43 myPC 01:f7:a4:67:4d:5f:8a
 
Well I'm at a complete loss. Your dnsmasq setup is effectively identical to mine.

The only thing I can think of is to try adding an entry for myPC into the router's DHCP Server Manually Assigned list and see if it resolves then.
 
When I tried that it hung dnsmasq. All nslookups timeout until I disable manual assignment and remove the assignment in the UI.
 
Code:
Mar 27 08:55:00 dnsmasq[7103]: duplicate dhcp-host IP address 192.168.1.43 at line 61 of /etc/dnsmasq.conf
Mar 27 08:55:00 dnsmasq[7103]: FAILED to start up
Mar 27 08:55:28 dnsmasq[7220]: duplicate dhcp-host IP address 192.168.1.43 at line 61 of /etc/dnsmasq.conf
Mar 27 08:55:28 dnsmasq[7220]: FAILED to start up
Mar 27 08:55:58 dnsmasq[7364]: duplicate dhcp-host IP address 192.168.1.43 at line 61 of /etc/dnsmasq.conf
Mar 27 08:55:58 dnsmasq[7364]: FAILED to start up
 
Doh! OK temporarily comment out the myPC entry in dnsmasq.conf.add and try again.
No dice :(

The proper dhcp-host line is added to /etc/dnsmasq.conf, but resolution still fails from clients or console.
 
Try using the FQDN when doing a lookup.
 
I'm going to try upgrading firmware or reset, whichever is necessary, but I'm keen to track it down before I do that. Seems like there might be some special edge case where this happens and I'd like to know what it is before I nuke it.
 
nslookup on the router's own name works.

Code:
$ nslookup RT-AX86U-AR28
Server:  RT-AX86U-AR28.foo.lan
Address:  192.168.1.1

Name:    RT-AX86U-AR28.foo.lan
Address:  192.168.1.1

So it seems that it's not local name resolution per se, but incorporating DHCP clients into the mix that has gone wrong somewhere.
 
Did you remove lines from your config in post #51? The error line in post #64 is not even close. If you didn't remove lines that might suggest your config file has non-visible corruption.

I would try temporarily disabling your dnsmasq.conf.add file and trying again. Note that you need to use the FQDN. I forgot that's something that's fixed in the current firmware.
Code:
mv /jffs/configs/dnsmasq.conf.add /jffs/configs/dnsmasq.conf.add.disabled
service restart_dnsmasq
nslookup mypc.foo.lan
 
Code:
admin@RT-AX86U-AR28:/jffs/configs# mv dnsmasq.conf.add dnsmasq.conf.old
admin@RT-AX86U-AR28:/jffs/configs# service restart_dnsmasq

Done.
admin@RT-AX86U-AR28:/jffs/configs# nslookup myPC.foo.lan
Server:    127.0.0.1
Address 1: 127.0.0.1 localhost.localdomain

nslookup: can't resolve 'myPC.foo.lan'
 
Code:
admin@RT-AX86U-AR28:/jffs/configs# mv dnsmasq.conf.add dnsmasq.conf.old
admin@RT-AX86U-AR28:/jffs/configs# service restart_dnsmasq

Done.
admin@RT-AX86U-AR28:/jffs/configs# nslookup myPC.foo.lan
Server:    127.0.0.1
Address 1: 127.0.0.1 localhost.localdomain

nslookup: can't resolve 'myPC.foo.lan'
OK
Code:
cd /etc
cat hosts
 
Code:
admin@RT-AX86U-AR28:/tmp/etc# cat hosts
127.0.0.1 localhost.localdomain localhost
192.168.1.1 RT-AX86U-AR28.foo.lan RT-AX86U-AR28
192.168.1.1 RT-AX86U-AR28.local
192.168.1.1 router.asus.com
192.168.1.1 www.asusnetwork.net
192.168.1.1 www.asusrouter.com
That explains why the router's host name works.
 
You should be seeing an entry for "mypc". So something's not right with the "manually assigned" DHCP entry. Is that still enabled?

Check that you haven't got a rogue /jffs/configs/hosts or /jffs/scripts/hosts.postconf
 
You should be seeing an entry for "mypc". So something's not right with the "manually assigned" DHCP entry. Is that still enabled?

Check that you haven't got a rogue /jffs/configs/hosts or /jffs/scripts/hosts.postconf
For some reason I'm not allowed to post ouput anymore
 
2022-03-27 10_28_01-Intermittent DNS failures _ Page 4 _ SmallNetBuilder Forums - Chromium.png

jquery is giving a 403 on post when I include my console output.
 
View attachment 40406
jquery is giving a 403 on post when I include my console output.
It's because you're not allowed to post text that contains "/etc" followed by "/hosts" (without a space). Just insert a space and we'll know what you mean.

I'm out of ideas. I would now just factory reset the router and start gain.
 
I'm out of ideas. I would now just factory reset the router and start gain.
That's the plan. I was just hoping to debug it before I do. I always hate to waste an opportunity to track down a bug (if it's a bug). It would be neat if there was an easy way to emulate the router environment so I could keep an image of the router as it is now and play with it in a virtual environment.
 

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