topic Re: Strange DNS Problems in Wireless

Strange DNS Problems

NunoFlora — Wed, 30 Mar 2022 10:55:51 GMT

I have a DNS problem in a network of 500 users, some devices connect to the wifi in one of the ssid and after connection ok they use chrome that tells them the dns did not respond i check the logs in meraki and see "DNS server did not respond".

I'm using google 8.8.8.8 and 8.8.4.4 but for some reason it gives me this errors but I can use a computer and ping 8.8.8.8 and 8.8.4.4 no problem but can't get dns in chrome our other web browser.

Re: Strange DNS Problems

aleabrahao — Wed, 30 Mar 2022 11:26:30 GMT

Is The Client IP assignment NAT mode or Bridge mode?

Re: Strange DNS Problems

inderdeepsingh1 — Wed, 30 Mar 2022 12:14:07 GMT

@NunoFlora : Check this thread

https://community.meraki.com/t5/Wireless-LAN/Weird-DNS-Issues/m-p/5352#M970

Re: Strange DNS Problems

Philip D'Ath — Thu, 31 Mar 2022 19:08:06 GMT

If you use nslookup, can you resolve a DNS name?

Chrome changed over to using DNS over HTTPS at some stage, so it may not be sending DNS queries as you think. I think it was optional initially and then became the default. You could try a test and disable DNS over HTTPS on one machine and see if that changes the problem.

https://pureinfotech.com/enable-dns-over-https-chrome/

Are you using any third-party filtering software, either for DNS or HTTPS?

Re: Strange DNS Problems

MerryAki — Sat, 02 Apr 2022 15:30:20 GMT

I would also mention DNS over TLS as a possible problem. Try to do a trace route anc check for rules that block traffic to the DNS Server/s.

Another thing that might be required at some point is DNSSEC, give 9.9.9.9 a chance. (Cloudflare is of course a good one, too, but not in terms of security and threat defending)

Re: Strange DNS Problems

securingnimbu5 — Sun, 03 Apr 2022 08:21:00 GMT

@MerryAki I have to agree with you here.

My thoughts:

If he can ping successfully, but can’t visit web pages through browsers; then we know the issue lies with “host names not resolving”.

I would capture the DNS traffic and find out where it’s getting dropped. Then check the ACL to see if DNS traffic is allowed on port 53. Cheers!

Re: Strange DNS Problems

NunoFlora — Tue, 12 Apr 2022 15:31:55 GMT

I still don't know what the problem is but changed dns to 1.1.1.1 and solved all the dns problems

Re: Strange DNS Problems

MerryAki — Tue, 12 Apr 2022 15:37:57 GMT

Or try preselecting Google or Cisco Umbrella DNS

But yes, cloudflare is performing better ✌️