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
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
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: A Complete Guide to Mechanisms and Modifiers
Master SPF record syntax with detailed explanations of every mechanism (include, ip4, a, mx, exists) and modifier (redirect, exp).
SPF vs DKIM vs DMARC: Understanding Email Authentication
What's the difference between SPF, DKIM, and DMARC? Learn how each protocol works and why you need all three for complete email security.
SPF PermError: Causes, Diagnosis, and Fixes
SPF PermError is a fatal authentication failure. Learn what causes it (syntax errors, 10-lookup limit, multiple SPF records) and how to fix it.
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.