How can DNS misconfigurations get you blocklisted?

DNS misconfigurations create signals that blocklist operators and mailbox providers interpret as negligence or malicious intent.

Common problems:

Missing SPF/DKIM: Legitimate senders configure authentication. Not having it suggests you're either incompetent or avoiding accountability.

Syntax errors: Malformed SPF records, missing semicolons in DKIM, or invalid DMARC policies cause authentication failures even when records exist.

Too many DNS lookups: SPF has a 10-lookup limit. Exceeding it causes permanent failures for all messages.

No reverse DNS: IPs without PTR records matching forward DNS look suspicious. Many systems reject connections from such IPs.

Expired or missing records: Records that existed during setup but were removed or changed break authentication.

Blocklist triggers: While DNS errors alone rarely cause blocklisting, they accelerate reputation damage. If you're already generating complaints, misconfiguration removes any benefit of the doubt.

DNS is foundational. Errors here affect every message you send. A lighthouse with a broken signal endangers every ship it was meant to guide.