[FR] Make Unbound Default to Recursive Queries First and Forward to Public Resolver on Failure

[kkkgo]

Current behavior Is there a current behavior that the feature relates to? The forward-first option is the opposite of what I'm looking for, as it forwards queries before attempting recursion.

Describe the desired feature I'm using Unbound to set up a recursive resolver, which works well most of the time. However, due to network issues, I sometimes have trouble connecting to some NS servers, resulting in DNS query failures. I would like to configure Unbound to default to using recursive queries for my DNS requests. When a recursive query fails, I want it to fall back and forward the query to a specified public DNS resolver for failover, while also caching the result.

I've reviewed the Unbound documentation, and it seems there isn't a specific option to achieve this functionality.

If there's a way to configure Unbound to meet this requirement, please let me know. I would greatly appreciate any guidance or assistance. Thank you!

Potential use-case Using Unbound as a recursive server can effectively safeguard privacy and ensure accurate DNS resolution results. However, due to network issues, DNS queries may occasionally fail. Adding this feature can strike a good balance between privacy protection, caching, and failover.

[kkkgo]

https://github.com/NLnetLabs/unbound/issues/51

[brianjmurrell]

Should this just be closed as a duplicate of #51?