DNS weirdness just with browsers

[Rhywden]

So, this is weird. For my school I have setup various domains and subdomains.

For instance, the main domain would be foo.de and I'd have several subdomains of the type: bar.foo.de and baz.foo.de

Today one of those subdomains always yields a NXDOMAIN or similar when I try to ping it or access it through the browser (Edge, Chrome, Firefox all the same). Just that one domain, though and only on this Windows 10 PC.

If I do nslookup on the CLI, it yields the proper address. Other computers in the same network work just fine.

ipconfig /flushDNS has already been tried as has been setting a different DNS provider. Rebooting did not help.

Does anybody else have any idea what to try?

[loopback0]

No-one's messed with the hosts file on that machine?

[Rhywden]

@loopback0 said in DNS weirdness just with browsers:

No-one's messed with the hosts file on that machine?

No. I just had a look. There's nothing in there which shouldn't be there.

[Rhywden]

@loopback0 But I just used the nuclear option and simply added the IP address of the subdomain into the HOSTS file (it won't change the IP address for the foreseeable future so there's that).

Working now. Still mystified as to where the problem comes from.

[PleegWat]

When you used nslookup on the CLI, did you look up using the authorative nameserver or the locally configured one? Could it just be a case of the ISP/google/whatever you're using nameserver not having the latest IP yet?

[Rhywden]

@PleegWat said in DNS weirdness just with browsers:

When you used nslookup on the CLI, did you look up using the authorative nameserver or the locally configured one? Could it just be a case of the ISP/google/whatever you're using nameserver not having the latest IP yet?

According to nslookup, it used the local one (non-authoritative, i.e. the router).

Also, the IP did change. Two weeks ago.

[sloosecannon]

@Rhywden said in DNS weirdness just with browsers:

@PleegWat said in DNS weirdness just with browsers:

When you used nslookup on the CLI, did you look up using the authorative nameserver or the locally configured one? Could it just be a case of the ISP/google/whatever you're using nameserver not having the latest IP yet?

According to nslookup, it used the local one (non-authoritative, i.e. the router).

Also, the IP did change. Two weeks ago.

It's possible Chrome cached an NXDOMAIN response somehow. Chrome (and presumably other browsers?) has its own DNS cache that's separate from the OS

[Zenith]

Chrome is fucking awful. What solved that problem with domain lookups failing, though was switching off of my ISP's DNS server to Cloudflare. But AVG (I suspect) would catch that after a certain period of time and revert it back until I finally slew that beast.

[sockpuppet7]

@Rhywden today I solved dell.com not resolving by changing my dns server from 1.1.1.1 to 8.8.8.8

[cheong]

@sloosecannon said in DNS weirdness just with browsers:

It's possible Chrome cached an NXDOMAIN response somehow. Chrome (and presumably other browsers?) has its own DNS cache that's separate from the OS

Yup. You have to go to chrome://net-internals/#dns to clear cache there.

https://superuser.com/questions/203674/how-to-clear-flush-the-dns-cache-in-google-chrome#:~:text=Navigate to chrome%3A%2F%2Fnet,"Clear host cache" button.&text="Go to tools -> options,but hey it seems to.

As mentioned in other replies there, touching the hosts file will also trigger refresh if the Chromium-based browser is running.

[Rhywden]

@sloosecannon said in DNS weirdness just with browsers:

@Rhywden said in DNS weirdness just with browsers:

@PleegWat said in DNS weirdness just with browsers:

When you used nslookup on the CLI, did you look up using the authorative nameserver or the locally configured one? Could it just be a case of the ISP/google/whatever you're using nameserver not having the latest IP yet?

According to nslookup, it used the local one (non-authoritative, i.e. the router).

Also, the IP did change. Two weeks ago.

It's possible Chrome cached an NXDOMAIN response somehow. Chrome (and presumably other browsers?) has its own DNS cache that's separate from the OS

Firefox has the same problem. As I said, it happens to all browsers and a ping from the CLI shows it as well.

Today one of those subdomains always yields a NXDOMAIN or similar when I try to ping it or access it through the browser (Edge, Chrome, Firefox all the same).

[JBert]

I wonder if your problems could be caused by the browser makers' insistence on using DNS over HTTP/S (DOH).

For sure it will make troubleshooting things with nslookup difficult, so try applying this article on how to enable it in reverse. I would imagine that if the option is on you could disable it by unchecking the appropriate checkboxes.

Though then again I wonder if they never contact the local DNS server at all, or if the whole DOH setup assumes that all your DNS records are publicly available (this assumption doesn't hold if your network has an internal DNS server returning internal hosts but a public DNS server which doesn't have those records - I believe that's called a "split-brain DNS" setup).

[Rhywden]

@JBert said in DNS weirdness just with browsers:

I wonder if your problems could be caused by the browser makers' insistence on using DNS over HTTP/S (DOH).

Doesn't explain why ping shows it as well.

[sloosecannon]

@Rhywden said in DNS weirdness just with browsers:

and a ping from the CLI shows it as well.

Oh I missed that.

What the fuck??