How to Fix the SPF Permerror Caused by Too Many DNS Lookups

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SPF records are limited to 10 DNS lookups, and exceeding that limit produces a permerror that many mail receivers treat as a failed check, raising the chance of messages landing in spam. The problem typically builds up gradually as more third-party services are added to send email on a domain's behalf. Mechanisms such as include, a, mx, ptr, exists and redirect count toward the limit, including nested lookups, while ip4, ip6 and all do not. Remedies suggested include removing unused senders, replacing a and mx with ip4 where servers have fixed addresses, dropping the deprecated ptr mechanism, and sending marketing mail from a subdomain with its own SPF record. The article also cautions that flattening includes can break silently when provider IPs change, and notes that DMARC can still pass through DKIM alignment.

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