Linux Server / Networking, SSH & Web Services
Check per-link resolver routing when an internal server name fails
A Linux server can use different resolvers for different domain suffixes. Reading one global nameserver line may miss split DNS.
Environment and inputs: Linux server baseline · Ubuntu 24.04 LTS / RHEL 9-style systems. Use the specified distribution, init system and installed tool; service names, privileges and supported options can differ.
Start with this check
Confirm the host, shell and access role. Replace sample names, paths, domains and interfaces with approved targets. These are diagnostic commands; assess policy and workload impact before making changes.
resolvectl status
resolvectl query app.corp.example.comRead the result
On hosts using systemd-resolved, the output shows link DNS configuration and a query through that service. Other resolver setups need their own tools.
Resolve and verify
Compare routing domains and the selected link with the intended internal DNS path. Repair configuration through the actual network manager and retest application resolution.
Before changing production
Do not overwrite a generated resolv.conf or send confidential internal names to an unrelated public resolver.