Sender Policy Framework (SPF): What It Is and How It Works
Learn how Sender Policy Framework (SPF) authorizes email senders, affects deliverability, and how to build, test, and maintain a valid SPF record.
Oct 19, 202623 min read
Dns
79 articles on dns.
Domain Already Registered: Resolve Email Sending Domain Conflicts
Domain already registered? Learn why email platforms lock domains, prove DNS ownership, and safely restore API and SMTP email sending quickly.
Oct 18, 202623 min read
DMARC Monitoring: How to Read Reports and Fix Email Authentication
Learn DMARC monitoring: configure aggregate reports, interpret SPF and DKIM alignment, identify unknown senders, and safely enforce policy.
Oct 18, 202620 min read
Blocklist Monitoring: How to Detect, Diagnose, and Recover From Email Listings
Learn blocklist monitoring for transactional email: detect IP and domain listings, interpret SMTP errors, fix root causes, and prevent recurrence.
Oct 17, 202627 min read
How to Add SPF, DKIM, DMARC, and Return-Path Records in Strato
Learn how to add SPF, DKIM, DMARC, and Return-Path DNS records in Strato without breaking mail delivery or domain verification.
Oct 17, 202620 min read
How to Add SPF, DKIM, DMARC, and Return-Path Records in GoDaddy
Complete GoDaddy SPF DKIM DMARC setup: add sender-authentication and return-path DNS records, avoid common host-name errors, and verify delivery.
Oct 17, 202619 min read
DMARC Record for Office 365: Configure Microsoft 365 Safely
Set up a DMARC record for O365 with correct SPF, DKIM, DNS syntax, monitoring, testing, and a safe path to quarantine or reject.
Sep 17, 202620 min read
DMARC Record Options: Every Tag, Policy, and Setup Choice Explained
Learn every DMARC record option, including p, rua, adkim, aspf, sp, np, and reporting tags. Build, test, and enforce DMARC safely.
Sep 17, 202621 min read
Email Routing Explained: How Messages Find the Right Destination
Learn how email routing works through MX records, SMTP relays, and inbox rules—and how to design reliable routes without harming deliverability.
Sep 14, 202622 min read
Dominio de correo electrónico: qué es y cómo protegerlo
Dominio de correo electrónico: descubre cómo autenticarlo, alinear SPF, DKIM y DMARC, y proteger la entrega de mensajes legítimos y esperados.
Sep 8, 202622 min read
DNS TXT Record: The Email Authentication Record Explained
Learn what a DNS TXT record is, how SPF, DKIM, and DMARC use it, and how correct DNS publishing protects email deliverability and trust.
Sep 8, 202621 min read
DKIM (DomainKeys Identified Mail): What It Is and How It Works
Learn what DKIM (DomainKeys Identified Mail) is, how email signatures work, why alignment affects delivery, and how to set up and troubleshoot DKIM.
Sep 8, 202623 min read
DMARC Record Validator: Check, Fix, and Test Your DNS Policy
Use a DMARC record validator to find DNS syntax, duplicate-record, alignment, and reporting errors—then test the policy with a practical example.
Sep 4, 202617 min read
SPF Email Authentication: What It Is, How It Works, and How to Fix It
Learn how SPF email authentication works, how SPF records are evaluated, common DNS errors, and practical steps to fix authorization failures fast.
Aug 29, 202623 min read
IP Address in Email Deliverability: Definition, Reputation, and Setup
Learn how an IP address affects email deliverability, sender reputation, reverse DNS, shared vs. dedicated IPs, warming, and troubleshooting.
Aug 27, 202623 min read
DMARC Record Type: TXT Syntax, Setup, Tags, and Examples
Learn the DMARC record type, exact TXT record syntax, required tags, reporting setup, validation steps, and mistakes that can break email authentication.
Aug 27, 202618 min read
Email Sending Domain: Definition, DNS Records, and Deliverability
Learn what an email sending domain is, how DNS authentication works, and how to protect deliverability, brand trust, and campaign performance.
Aug 26, 202626 min read
How to Add SPF, DKIM, and DMARC Records in DigitalOcean DNS
Learn how to add SPF, DKIM, DMARC, and return-path records in DigitalOcean DNS, avoid hostname errors, and verify email authentication.
Aug 18, 202619 min read
How to Add SPF, DKIM, and DMARC Records in Squarespace
Learn how to add SPF, DKIM, DMARC, and return-path DNS records in Squarespace without broken hosts, duplicate SPF, or alignment issues.
Aug 18, 202621 min read
Hetzner SPF DKIM DMARC Setup: Add Email DNS Records Correctly
Set up SPF, DKIM, DMARC, and return-path DNS records for a Hetzner domain. Avoid host-name errors, verify alignment, and protect delivery.
Aug 18, 202621 min read
DreamHost SPF, DKIM, and DMARC Setup for Email Domains
Set up DreamHost SPF, DKIM, DMARC, and return-path DNS records correctly to authenticate email, pass alignment, and avoid common DNS mistakes.
Aug 18, 202620 min read
IONOS SPF, DKIM, and DMARC Setup for Sending Domains
Set up IONOS SPF, DKIM, DMARC, and return-path DNS records correctly, avoid hostname mistakes, and verify your sending domain for email.
Aug 18, 202618 min read
Gandi SPF, DKIM, and DMARC Setup for Sending Email
Set up SPF, DKIM, DMARC, and a custom return-path for a Gandi domain with exact DNS record shapes, dashboard steps, and fixes for common errors.
Aug 18, 202621 min read
How to Add SPF, DKIM, DMARC, and Return-Path Records in Porkbun
Learn how to add SPF, DKIM, DMARC, and return-path DNS records in Porkbun, avoid host-field mistakes, and verify email authentication.
Aug 18, 202623 min read
Namecheap SPF, DKIM, and DMARC Setup for Sending Domains
Set up Namecheap SPF, DKIM, DMARC, and return-path DNS records correctly, avoid host-field mistakes, and verify your email domain.
Aug 17, 202621 min read
How to Add SPF, DKIM, DMARC, and Return-Path Records in GoDaddy
Add SPF DKIM DMARC records in GoDaddy with the right TXT and CNAME values, avoid hostname mistakes, and verify your email domain step by step.
Aug 17, 202621 min read
How to Add Route 53 Email Authentication Records for SPF, DKIM, and DMARC
Add Route 53 email authentication records correctly with this practical guide to SPF, DKIM, DMARC, return-path DNS, testing, and fixes.
Aug 17, 202619 min read
How to Add SPF, DKIM, and DMARC Records in Cloudflare
Learn how to add SPF, DKIM, DMARC, and return-path DNS records in Cloudflare, avoid host-name errors, and verify your sending domain.
Aug 17, 202620 min read
How to Add DKIM and Return-Path Records to DigitalOcean DNS
Learn how to add DKIM and Return-Path records to DigitalOcean DNS, verify SPF alignment, prevent bounce issues, and test email authentication.
Aug 17, 202620 min read
Troubleshooting Email Delivery Issues: A Developer’s Guide
Troubleshooting email delivery issues? Diagnose API, SMTP, DNS, authentication, bounces, spam placement, and recipient-side failures systematically.
Aug 17, 202623 min read
How to Send Email on Behalf of Your Customers Safely
Learn how to send email on behalf of customers with custom domains, SPF, DKIM, DMARC, bounce handling, tenant isolation, and testing.
Aug 17, 202622 min read
How to Send Email From Subdomains: DNS Setup and Deliverability
Learn how to send email from subdomains with SPF, DKIM, DMARC, return-path, and tracking DNS records, plus practical testing and troubleshooting.
Aug 17, 202623 min read
Raw DMARC Reports API: How to Retrieve, Export, and Parse Them
Learn how to retrieve raw DMARC reports from an API, request XML when supported, preserve originals, parse RUA data, and troubleshoot access.
Aug 16, 202622 min read
Getting Started With DMARC Digests: Configure, Read, and Use RUA Reports
Learn how to configure DMARC digests, receive RUA aggregate reports, interpret SPF/DKIM alignment, and move safely toward enforcement.
Aug 16, 202624 min read
DMARC FAQ: Setup, Alignment, Policies, and Reports
DMARC FAQ for developers: learn record syntax, SPF and DKIM alignment, p=none to reject policies, aggregate reports, and debugging steps.
Aug 16, 202619 min read
Resolving SPF Too Many DNS Lookups Errors: A Practical Guide
Resolve SPF too many DNS lookups errors with a clear audit, safe record changes, flattening guidance, testing steps, and delivery advice.
Aug 15, 202620 min read
How to Update an SPF Record When One Already Exists
Learn how to update an SPF record when one already exists, merge authorized senders, avoid PermError, and validate DNS safely.
Aug 15, 202621 min read
DKIM Record Won’t Verify? A Practical DNS Troubleshooting Guide
Fix a DKIM record that won’t verify: check the selector, DNS host and value, CNAME/TXT conflicts, propagation, signing, and DMARC alignment.
Aug 15, 202620 min read
How Often Should You Generate a New DKIM Key?
Learn how often to generate a new DKIM key, when emergency rotation is required, and how to rotate selectors without breaking email delivery.
Aug 15, 202619 min read
How to Verify a Domain for Transactional Email Sending
Learn how to verify a domain for email sending with DNS, SPF, DKIM, DMARC, validation commands, troubleshooting, and deliverability checks.
Aug 15, 202621 min read
Setting Up DKIM for Your Domain: DNS Records, Testing, and Troubleshooting
Set up DKIM for your domain with correct DNS records, selector guidance, testing commands, key rotation, and fixes for common failures.
Aug 15, 202620 min read
What Is SPF and Why Is It Important for Email?
Learn what SPF is, how SPF DNS records work, why it matters for email security and deliverability, and how to configure and test it correctly.
Aug 15, 202622 min read
What Is DKIM? A Developer’s Guide to Email Authentication
What is DKIM? Learn how DKIM email signatures, DNS selectors, key rotation, and DMARC alignment protect messages and support deliverability.
Aug 15, 202623 min read
How to Fix ISP Blocks: A Practical Email Deliverability Guide
Learn how to fix ISP blocks with a proven process for diagnosing SMTP errors, repairing DNS authentication, reducing complaints, and restoring delivery.
Aug 14, 202622 min read
How to Fix Hard Bounces: A Developer’s Troubleshooting Guide
Learn how to fix hard bounces by decoding SMTP errors, validating recipients, repairing DNS authentication, and protecting your sender reputation.
Aug 14, 202621 min read
Troubleshooting 422 Unprocessable Entity Errors in Email APIs
Troubleshoot 422 Unprocessable Entity errors in email APIs with a practical guide to payload validation, sender domains, DNS, SMTP, and retries.
Aug 14, 202621 min read
Common SMTP Connection Errors: Causes, Tests, and Fixes
Troubleshoot common SMTP connection errors with practical tests for ports, TLS, authentication, DNS, relaying, timeouts, and delivery replies.
Aug 13, 202627 min read
SMTP Codes: What They Are and How to Troubleshoot Them
Learn what SMTP codes mean, how to separate temporary from permanent failures, and troubleshoot delivery, DNS, TLS, and reputation issues.
Aug 13, 202625 min read