Why sometimes DNS (8.8.8.8) gets unreachable from fortigate

[Umesh]

Dear All,

I have observed sometimes google dns gets unreachable from fortigate which is configured public DNS server under DNS setting. I am using two public DNS server (google 8.8.8.8) and fortigate (96.45.46.46).

No setting used like DNS over TLS and DNS over HTTPS.

I just want to know if anyone has experienced this issue and what have you done to resolve the issue.

Thanks

[VinayHM]

Please refer to the article.

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-DNS-Filter-Rating-Server-Unreachable...

[Toshi_Esumi]

Not sure the cause but our multiple FGT HA pairs almost always have problems reaching those FTNT's DNS servers time to time. So we always change the default DNS server setting (FTNT's DNS) to Google DNS for new FGT installations. If even Google DNS has problem, there must be a network issue somewhere you need to find out.

Toshi