Conditional forwarder works on one server only

Minimal guidance for messy support realities.

Scenario

A conditional forwarder resolves properly from one DNS server, but not from others in the same environment.

Recommended Resolution Path

  1. Check replication scope of the forwarder and whether it was stored in AD-integrated config.
  2. Verify reachability from each DNS server to the upstream resolver.
  3. Compare firewall, DNS recursion, and root hint behavior between working and failing servers.
  4. Avoid client-side host hacks until the authoritative forward path is healthy.

Technician Notes

Document what changed, what confirmed the fix, and whether the issue points to a broader standards gap worth addressing for the client.