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DNS lookup limit

An SPF record ↗ lists which servers are authorized to send email for your domain. SPF records can reference other domains and services (for example, using include: or mx mechanisms), and each such reference requires a separate DNS lookup to verify. The SPF specification (RFC 7208) ↗ limits the total number of these lookups to 10 per SPF check. If your SPF record exceeds this limit, receiving mail servers may treat the SPF check as a permanent error and reject or flag your emails.

To check if your SPF records are compliant with the SPF specification:

  1. Log in to the Cloudflare dashboard ↗, and select your account and domain.
  2. Go to Email > DMARC Management.
  3. In Email record overview, select View records.
  4. Find your SPF record, and select the three dots next to it > Edit.
  5. DMARC Management will inspect your records and check for the total number of DNS lookups. If the record exceeds the limit, DMARC Management will display a warning. To fix this, remove unnecessary entries in your SPF record. Refer to Manage DNS records for more information.