SPF & Email Authentication Blog
Expert guides, DNS record explanations, and email security tips to secure your domain's outgoing mail validation.
What is SPF? Email Authentication and Deliverability Explained (2026 Guide)
Learn what Sender Policy Framework (SPF) is, how it works with DNS TXT records, and why it is critical to keep your emails out of the spam folder.
How to Solve the SPF 10 DNS Lookup Limit Error (2026 Flattening Guide)
Understand the RFC 7208 restriction that limits SPF records to 10 DNS lookups, and learn practical strategies to flatten your records.
Hard Fail vs Soft Fail: Configuring the SPF ~all Modifier
Compare the differences between SPF Soft Fail (~all) and Hard Fail (-all) policy options, and learn which one is safer for your domain.
SPF Record Syntax: Complete Mechanisms & Modifiers Guide (2026)
2026 complete SPF syntax reference: every mechanism (include, ip4, a, mx, exists), redirect/exp modifiers, qualifiers and lookup-safe tested examples.
SPF vs DKIM vs DMARC: Complete Email Authentication Guide (2026)
2026 comparison: how SPF authorizes servers, DKIM signs cryptographically and DMARC enforces alignment with rua/ruf reporting — plus Gmail/Yahoo rollout order.
SPF PermError: Causes, Diagnosis, and Fixes (2026 Troubleshooting Guide)
2026 fix guide: SPF PermError fatal failures from syntax errors, duplicate records, 10-lookup limit breaches and DNS timeouts — with flattening and include-audit remedies.
How to Create an SPF Record for Multiple Email Providers
Modern businesses use multiple email services. Learn how to create a single SPF record that authorizes Google Workspace, Microsoft 365, SendGrid, and more.
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