What happens when DNS lookups time out during delivery?

DNS timeout effects on email:

During sending:

MX lookup timeout = cannot find recipient server

Sender queues and retries later

Persistent failure may bounce mail

During receiving (authentication):

SPF lookup timeout = temperror result

DKIM key lookup timeout = signature unverifiable

DMARC lookup timeout = no policy applied

Receivers typically treat temperror as "try again later" rather than fail.

Resolution:

Use reliable DNS hosting

Multiple nameservers for redundancy

Monitor DNS availability

Occasional timeouts are handled gracefully. Persistent issues cause delivery problems.

Temporary registry unavailability causes processing delays. Ships wait and retry.