---
source: crates/llm-assisted-api-debugging-lab/tests/reports.rs
expression: rendered
---
CASE: dns_config
RULE: dns_failure
SEVERITY: critical (author judgment: connection never reached the API; no application-layer traffic is flowing)
LIKELY CAUSE: DNS resolution failed for upstream host "api.exmaple.com"
EVIDENCE:
- DNS resolution failed for api.exmaple.com: no such host
HYPOTHESES (consistent with evidence; not asserted as fact):
- Hostname is misspelled or points at the wrong environment.
- Local resolver or upstream DNS provider is failing.
- Private DNS zone is not reachable from this network.
UNKNOWNS (do not invent answers):
- Whether other hostnames resolve from the same environment.
- Recent DNS, hosts-file, or VPN configuration changes.
REPRODUCTION:
cargo run -p llm-assisted-api-debugging-lab -- diagnose dns_config
NEXT STEPS:
1. Confirm the hostname character-for-character against documentation.
2. Run `dig <host>` or `getent hosts <host>` from the affected environment.
3. Check whether the DNS resolver was changed recently (e.g. systemd-resolved, VPN).
4. Retry from a known-good network to isolate environment from configuration.
ESCALATION NOTE:
Connection never reached the API: name resolution for the upstream host failed. Until DNS resolves, no application-level diagnosis is possible.