DMARC
DMARC Checker
Check a domain DMARC record, policy, alignment tags, reporting address, and common Gmail sender issues.
Email DNS diagnostics
Check the records that decide whether business email looks trustworthy.
Start with a live DMARC, SPF, DKIM, MX, or Gmail bulk sender check. Results include the record found, risk level, and copy-ready repair notes.
DMARCp=quarantine
SPF1 record, 4 lookups
DKIMselector needed
MX2 hosts resolve
Tools
Launch set
SPF
SPF Checker
Validate SPF syntax, multiple-record conflicts, DNS lookup pressure, and risky all mechanisms.
DKIM
DKIM Checker
Check a DKIM selector TXT record and verify whether the public key is published correctly.
MX
MX Lookup
Look up MX records, priority order, null MX behavior, and host resolution status.
GEN
DMARC Record Generator
Generate a DMARC TXT record with policy, reporting, alignment, percentage, and subdomain settings.
GEN
SPF Record Generator
Create an SPF TXT record for common senders, custom includes, IP addresses, and all policy choices.
HDR
Email Header Analyzer
Paste raw email headers and inspect Authentication-Results, SPF, DKIM, DMARC, and Received chains in your browser.
GMAIL
Gmail Bulk Sender Compliance Checker
Check a domain against the DNS-authentication parts of Gmail bulk sender requirements.
SEO guides
Long-tail content built around real fixes
Gmail 5.7.26 Fix
A practical checklist for fixing Gmail 5.7.26 authentication rejections and sender requirement issues.
SPF Softfail vs Fail
Understand SPF ~all and -all policies and how to move a sender domain safely toward a stricter SPF posture.
DMARC Alignment Checker
Learn how DMARC alignment works and how to confirm alignment with DNS and email headers.
How to Read a DMARC XML Report
A beginner-friendly explanation of DMARC aggregate XML report fields and how to use them during policy migration.
Bulk Sender Requirements Checker
Check the DNS side of bulk sender readiness before reviewing message-level and reputation requirements.
DMARC Record Not Found: How to Fix It
Fix a DMARC record not found error by checking the DNS host, TXT value, propagation, and duplicate records.
Multiple SPF Records: How to Merge Them Safely
Learn why multiple SPF records cause permerror and how to merge includes, IP addresses, and the final all mechanism.
SPF Permerror: Too Many DNS Lookups
Diagnose and fix the SPF ten-DNS-lookup limit without hiding unauthorized senders or breaking legitimate email.
DKIM Selector Not Found: Troubleshooting Guide
Find the correct DKIM selector and fix missing TXT or CNAME records for Google Workspace, Microsoft 365, and email platforms.
SPF Pass but DMARC Fail: Why It Happens
Fix DMARC failures when SPF passes for a return-path domain that does not align with the visible From address.
DKIM Pass but DMARC Fail: Fix Signing Alignment
Understand why a valid DKIM signature can still fail DMARC and configure an aligned custom signing domain.
DMARC p=none vs quarantine vs reject
Choose a DMARC policy and move safely from monitoring to enforcement without blocking legitimate mail.
Authentication-Results Header Explained
Read an Authentication-Results email header and identify SPF, DKIM, DMARC, alignment, and the trusted receiving server.
Gmail 550-5.7.26 Unauthenticated Email Fix
Troubleshoot Gmail 550-5.7.26 by testing SPF, DKIM, DMARC, alignment, PTR, TLS, and the actual sending stream.
Gmail One-Click Unsubscribe Requirements
Understand List-Unsubscribe, one-click POST handling, visible unsubscribe links, and what DNS tools cannot verify.