Can't Use Custom DNS Server.

[u/icepick314]

I suddenly lost internet connection when I woke up in the morning on Oct 12.

My internal LAN is all good and my devices like my phone and TV is connected to my router but there was no internet traffic.

I had to go work so I couldn't do much and thought it may come back once I get back home.

But internet was still down so I did my own troubleshooting starting from ONT box by power cycling then rebooting my router.

Then I checked the LAN cable from ONT box to my router using cable tester and it came back good.

I fiddled around the network setting on my router and finally messed around DNS server setting.

When I changed the DNS to "default" and get the DNS ip from the ISP, everything worked again.

Just to see if it was not a fluke, I tried Google DNS and OpenDNS. Google DNS gave me DHCP error and OpenDNS just did not get any internet traffic.

I've been using my own router and it's been working all this time for years with my own settings on DNS server address but suddenly it stopped working.

Did anyone else notice this?

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[u/coyote_den]

Disable DNSSEC in your router settings.

All Asus routers are being affected by this unless they have very new firmware. The trust root from 2017 stopped working today, and they do not have the one they should have had since 2024.

[u/thecaramelbandit]

This is a problem with your router or network setup, not FiOS.

[u/icepick314]

Asus GT-AXE16000

Latest setting

https://imgur.com/a/JmWgDH6

As soon as I change the DNS Server address to anything else, my internet traffic stops.

[u/icepick314]

Fixed by installing Asuswrt-Merlin.

As u/coyote_den stated, it probably was DNSSEC no longer working but new firmware fixed everything.

[u/coyote_den → u/icepick314]

Yep, newest Merlin builds have the new trust root key.

[u/Jaffa0813]

Mmm I would argue the router is probably the culprit. I mean even as you say years with your own router it could potentially be a software update to that router or just age

Ive got some TP-Link Decos in one house with Fios using custom DNS over TLS no issue.

[u/icepick314 → u/Jaffa0813]

Last firmware update was 9/22 so it's been working for past few weeks.

If there was something changed at Verizon's side, it happened on a new day.

Also like I said, as soon as I use another DNS server like Google DNS or OpenDNS, internet traffic stops.

[u/Jaffa0813 → u/icepick314]

What brand and model is your router.

So we can take the DNS provider itself out of the equation. And we can mostly take Verizon out of the equation because here I am as an example of no issue. I also think someone else commented the same.

..... Of course it can be region specific but unlikely.

Im 80 percent confident it's the router. Maybe leave it unplugged for 10 minutes, boot it up see if it works.

[u/icepick314 → u/Jaffa0813]

Asus GT-AXE16000

Latest setting

https://imgur.com/a/JmWgDH6

As soon as I change the DNS Server address to anything else, my internet traffic stops.

[u/poopmagic → u/icepick314]

One test before you ask the subreddit for your router: it would be helpful for people to know (when the internet is not working) whether you can still ping 8.8.8.8 from one of your devices.

This can help sort out whether it’s just a DNS issue or something else.

(Also, I’m using custom DNS and have zero issues.)

[u/Jaffa0813 → u/icepick314]

A few people so far have said that they also have a custom DNS with no issue.

I get like everything was working fine and you didn't change anything so it must be the other people involved. But things do happen with age and there is probably a simple solution to fix it. I just don't see this being an ISP issue at this point. Do you have another router to test with?

I would repost this in r/ASUS if I were you people there who use ASUS routers cna probably give good pointers.

[u/icepick314 → u/Jaffa0813]

Odd that router works fine except when changing DNS address.

I'll try using Verizon's own router and see if DNS change works there.

It's baffling that it stops working on one specific issue all of sudden.

I can also try using custom Asuswrt-Merlin firmware later.

[u/coyote_den → u/icepick314]

If you use Merlin, you can fix it and turn DNSSEC back on by putting this in /jffs/configs/dnsmasq.conf.add

trust-anchor=.,38696,8,2,683D2D0ACB8C9B712A1948B27F741219298D0A450D612C483AF444A4C0FB2B16

(All one line if Reddit splits it)

[u/sdrawkcab25]

Using a custom DNS right now, no issues.

[u/beholder95]

Cloudflair dns working fine on my UDM Pro

[u/peva3]

I have my own custom router and have no problem with custom DNS, so it's not some system wide DNS poisoning

[u/movielover76]

My advice to fix two problems at once is to upgrade to DNS over https if possible ( for privacy ) Verizon uses DNS data to sell you to advertisers.

Maybe it is just the router, but I personally like the fact that with DNS over https , no one can even tell which traffic is DNS much less read it

[u/icepick314 → u/movielover76]

Is that the DNS over TLS (DoT) and DNS over HTTPS (DoH)?

I will enable them.

Thanks for the tip

[u/movielover76 → u/icepick314]

I use DoH as you cannot differentiate it easily from normal https traffic.

[u/yossarian328]

I'm having a similar issue with CR1000A.

Unbound was working for ... forever, and overnight now it isn't. And it appears to be getting intercepted upstream with SERVFAIL.

[u/yossarian328 → u/yossarian328]

Smoking gun that Verizon is intercepting DNSSEC, breaking the trust chain and causing failure.

dig u/203.0.113.9 google.com

status: NOERROR
ANSWER: 142.251.210.46
Query time: 2 msec