DNS_PROBE_STARTED / DNS_PROBE_FINISHED_NXDOMAIN / ERR_CONNECTION_REFUSED

MicaelO

Hi,
I have this strange problem with a USG40.
Seems like it's at times refuses to let DNS Requests pass through.
Computers in the LAN won't be able to visit sites, then all upp the sudden they can.
They may need to try like 5-10 times before the site show up.

DNS_PROBE_STARTED / DNS_PROBE_FINISHED_NXDOMAIN / ERR_CONNECTION_REFUSED are all errors that have been displayed while they can't access the websites.

Does anyone have any ideas what this could be?

The windows server on the LAN serves as a DNS server and has forwarders set up for the ISP's DNS servers, have also tried to use 8.8.8.8 and the USG40 as forward adresses, but the problem persists.

PeterUK

What if you set a PC device with DNS for 8.8.8.8?

MicaelO

PeterUK said:

What if you set a PC device with DNS for 8.8.8.8?

Sorry, should have mentioned that I have tried that as well...

Zyxel_Emily

Hi @MicaelO,

 

Use the command to check if the DNS server provided by ISP works.

Router> nslookup <hostname/IP> server <DNS server's IP>

Example:

Router> nslookup  www.zyxel.com server 168.95.195.100

 

You can also add an extra DNS server manually.

The three errors may come from DNS cache/Chrome or other software on Windows.

Here are some methods for your reference.

DNS_PROBE_STARTED

https://answers.microsoft.com/en-us/windows/forum/windows_10-networking/error-dnsprobestarted-dnsprobefinishednxdomain/138d7c90-1f9a-47ba-b5e4-062751bc67fc

DNS_PROBE_FINISHED_NXDOMAIN

https://www.drivereasy.com/knowledge/fix-dns-probe-finished-nxdomain-chrome/

ERR_CONNECTION_REFUSED 

https://medium.com/@sslsecurity/what-is-err-connection-refused-error-in-chrome-and-how-to-fix-it-7bfdb1ea2b61

Mattcc

Hi,

best fix is to change dns to 8.8.8.8 and 8.8.4.4, and flush dns

https://geeksadvice.com/how-to-fix-dns_probe_finished_nxdomain-error/

Zyxel_Cooldia

Hi @Mattcc ,

Welcome to Zyxel Community. ?

Thanks for information sharing.