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Deep dives into SPF limits, flattening, subdomains, and best practices.

Already comfortable with SPF basics? These articles cover the trickier parts of SPF management — the 10 DNS lookup limit, when flattening makes sense (and when it doesn't), using subdomains to split sending services, and the best practices that keep your SPF record clean as your email infrastructure grows.

SPF 10 DNS Lookup Limit Explained

Understand the SPF 10 DNS lookup limit — what counts, what doesn't, how to count your lookups, common provider costs, and strategies to stay under the limit.

SPF Flattening: Pros and Cons

Learn what SPF flattening is, when it makes sense, the risks of replacing includes with IP addresses, and better alternatives for staying under the 10-lookup limit.

SPF Records for Subdomains: Do You Need Them?

Learn when subdomains need their own SPF records, how subdomain SPF inheritance works, and how to use subdomains to solve the 10 DNS lookup limit.

SPF Record Best Practices

Best practices for creating and maintaining SPF records. Learn the right policy settings, how to audit your authorized senders, and how to keep your record clean.

SPF, DKIM, and DMARC: Complete Setup Guide

Set up all three email authentication protocols — SPF, DKIM, and DMARC — in the right order. A practical guide to complete email authentication.