Troubleshooting DNS Issues

[tissuelord]

Hello everyone,

I've recently jumped into Opnsense with a DEC2750, and everything has gone swimmingly well for the initial few months. Since December, however, I've been running into some weird issues with DNS and I've already reached a stump in my troubleshooting process.

My current setup is as follows:
Client -> AdGuard Home -> Unbound

The primary issue: DNS resolutions are slow. This is corroborated by the "Response" columns in AdGuard Home showing up to 10 seconds in processing, other users noticing slow page load times and timeouts, and via testing via Interfaces > Diagnostics > DNS Lookup.

Things that I have tried:

• Enable Query Forwarding in Unbound - this does not solve the issue
• Switch from Unbound to Dnsmasq - the response time issues still persist
• Use DNS server configurations in AGH - response times become consistent

While I can use the third solution and be done with it, the DNS lookup problems in the firewall remain (spiking up to 10 seconds in query response times). It also doesn't make sense: why would DNS directly via AGH work fine, but not when I use Opnsense as upstream?

Your insights on the matter would be greatly appreciated!