Custom WAN DNS not working

[Gary_Dexter]

Setting my WAN DNS to Custom and choosing Quad9 doesn’t seem to work and DNS stays as ISP’s DNS (as shown in the GUI on the Network Map and using nslookup - WAN DNS page states it’s “using” Quad9).

Is this a known bug?

GT-AC2900 running Merlin 386.12

 

[cptnoblivious]

What's entered in your LAN | DHCP | DNS entries?

Probably best to include a couple of screenshots.

 

[Gary_Dexter]

LAN DHCP DNS is set to the IP Address of my raspberry pi (running AGH and Unbound).

 

[Tech9]

No one mentioned it in 386.12 thread?

Folks will start explaining you what DNS your LAN devices use, etc. As I remember you know what are you doing and your question is about some non-sticking GUI setting around WAN DNS. Correct?

 

[Gary_Dexter]

No one mentioned it in 386.12 thread?

Folks will start explaining you what DNS your LAN devices use, etc. As I remember you know what are you doing and your question is about some non-sticking GUI setting around WAN DNS. Correct?

Yes. I know what I’m doing with regards to redirecting LAN devices to my rpi. But that’s not the issue.

The issue/question is why the router is still using my ISP’s DNS for WAN queries, when I’ve set it to use Quad9.

Cheers!

 

[dave14305]

If there are no browser console errors when you save the DNS settings, it could be something obscure with Dual WAN, even if you don’t use it. This thread sounded similar:

Solved - Router ignoring DNS settings

Hello! Today, I had some DNS issues (some URLs not beeing resolved). After checking, it seems, my RT-AX88U (Firmware:3004.388.4) is ignoring the DNS server setting for its own queries (and maybe even for other queries as well, cannot check), and forces Cloudflare's 1.0.0.2 for some reasons...

www.snbforums.com

 

[Gary_Dexter]

If there are no browser console errors when you save the DNS settings, it could be something obscure with Dual WAN, even if you don’t use it. This thread sounded similar:

Solved - Router ignoring DNS settings

Hello! Today, I had some DNS issues (some URLs not beeing resolved). After checking, it seems, my RT-AX88U (Firmware:3004.388.4) is ignoring the DNS server setting for its own queries (and maybe even for other queries as well, cannot check), and forces Cloudflare's 1.0.0.2 for some reasons...

www.snbforums.com

Hi Dave - tried that too - no luck.. no manual entries anywhere.

Anything/where else to check?

 

[dave14305]

Hi Dave - tried that too - no luck.. no manual entries anywhere.

Anything/where else to check?

See what’s in nvram.

nvram show | grep -E "^wan[01]?_dns"

 

[Gary_Dexter]

See what’s in nvram.

nvram show | grep -E "^wan[01]?_dns"

wan0_dns=212.23.3.100 212.23.6.100
wan0_dns1_x=9.9.9.9
wan0_dns2_x=149.112.112.112
wan0_dnsenable_x=0
wan1_dns=
wan1_dns1_x=
wan1_dns2_x=
wan1_dnsenable_x=1
wan_dns=212.23.3.100 212.23.6.100
wan_dns1_x=9.9.9.9
wan_dns2_x=149.112.112.112
wan_dnsenable_x=0

 

[dave14305]

wan0_dns=212.23.3.100 212.23.6.100
wan0_dns1_x=9.9.9.9
wan0_dns2_x=149.112.112.112
wan0_dnsenable_x=0
wan1_dns=
wan1_dns1_x=
wan1_dns2_x=
wan1_dnsenable_x=1
wan_dns=212.23.3.100 212.23.6.100
wan_dns1_x=9.9.9.9
wan_dns2_x=149.112.112.112
wan_dnsenable_x=0

The fields seem out of sync. Try switching to use the ISP DHCP DNS, save, then switch back to Quad9 and save. Then rerun the command.

 

[Gary_Dexter]

The fields seem out of sync. Try switching to use the ISP DHCP DNS, save, then switch back to Quad9 and save. Then rerun the command.

Hi Dave - I seem to remember doing that yesterday but will try it again now and post back the results in a few minutes.

 

[Gary_Dexter]

The fields seem out of sync. Try switching to use the ISP DHCP DNS, save, then switch back to Quad9 and save. Then rerun the command.

After switching to ISP DNS:

wan0_dns=
wan0_dns1_x=9.9.9.9
wan0_dns2_x=149.112.112.112
wan0_dnsenable_x=1
wan1_dns=
wan1_dns1_x=
wan1_dns2_x=
wan1_dnsenable_x=1
wan_dns=212.23.3.100 212.23.6.100
wan_dns1_x=9.9.9.9
wan_dns2_x=149.112.112.112
wan_dnsenable_x=1
size: 73823 bytes (57249 left)

Then switching back to Quad9:

wan0_dns=212.23.3.100 212.23.6.100
wan0_dns1_x=9.9.9.9
wan0_dns2_x=149.112.112.112
wan0_dnsenable_x=0
wan1_dns=
wan1_dns1_x=
wan1_dns2_x=
wan1_dnsenable_x=1
wan_dns=212.23.3.100 212.23.6.100
wan_dns1_x=9.9.9.9
wan_dns2_x=149.112.112.112
wan_dnsenable_x=0
size: 73919 bytes (57153 left)

 

[dave14305]

Definitely seems odd/unpredictable, but if cat /tmp/resolv.conf contains the right servers, then it’s just a GUI bug/quirk.

 

[Gary_Dexter]

Definitely seems odd/unpredictable, but if cat /tmp/resolv.conf contains the right servers, then it’s just a GUI bug/quirk.

cat /tmp/resolv.conf
nameserver 212.23.3.100
nameserver 212.23.6.100

 

[dave14305]

Ok, that’s a real problem then.

 

[Tech9]

@Gary_Dexter, use the universal solution. You know what it is. Have a good next weekend.

 

[Gary_Dexter]

Ok, that’s a real problem then.

So.. factory reset and start again from scratch?

 

[Tech9]

 

[Gary_Dexter]

Ok, that’s a real problem then.

Can I not just update the resolv.conf file manually?

 

[dave14305]

Can I not just update the resolv.conf file manually?

No but you could overwrite nvram entries and see if it sticks.

nvram set wan_dns="9.9.9.9 149.112.112.112"
nvram set wan0_dns="9.9.9.9 149.112.112.112"
nvram commit

Then reboot when you can.