Mail Authentication Checker

Emails often go to spam when your domain lacks proper authentication records. Gmail and Yahoo now require SPF, DKIM, and DMARC for bulk senders as of 2024-2025.

• Missing or incorrect SPF records
• No DKIM signatures on outgoing emails
• DMARC policy set to 'reject' without proper setup
• Third-party email services not authenticated

Yes, all three provide different layers of protection. SPF authorizes sending servers, DKIM signs messages cryptographically, and DMARC defines policies when authentication fails.

• SPF alone: Breaks when emails are forwarded
• DKIM alone: Doesn't prevent domain spoofing
• DMARC: Requires SPF or DKIM to work effectively

DMARC alignment requires the 'From' header domain to match either SPF or DKIM domains. Strict alignment needs exact matches, while relaxed allows subdomains.

• Strict: From: @example.com must match Return-Path: @example.com
• Relaxed: From: @example.com can match @mail.example.com
• Most domains should use relaxed alignment initially

Authentication can fail due to DNS propagation delays, incorrect record syntax, or third-party services. Allow 48-72 hours after DNS changes and verify record syntax.

• DNS propagation can take up to 72 hours
• Multiple SPF records cause permanent failures
• DKIM keys must match between DNS and email server
• Third-party services need separate SPF includes

Start with 'p=none' for monitoring, then gradually move to 'p=quarantine' and finally 'p=reject'. This prevents legitimate emails from being blocked during initial setup.

• Phase 1: p=none (monitor only, no action)
• Phase 2: p=quarantine (send failures to spam)
• Phase 3: p=reject (block failures completely)
• Monitor DMARC reports before progressing

DKIM keys should be rotated every 6-12 months minimum. Some services offer automatic rotation every 120 days. Longer keys (2048-bit) provide better security than 1024-bit.

• Rotate keys every 6-12 months minimum
• Use 2048-bit keys for better security
• Keep old keys active during transition period
• Stolen DKIM keys allow domain impersonation

While SPF, DKIM, and DMARC significantly reduce spoofing, attackers can still spoof display names or use similar-looking domains. BIMI (Brand Indicators) adds visual verification in 2025.

• Display name spoofing still possible
• Lookalike domains (examp1e.com vs example.com)
• BIMI provides visual brand verification
• User education remains important

DMARC reports show which sources send email for your domain, authentication results, and policy actions taken. They help identify legitimate senders and potential threats.

• Aggregate reports: Daily summaries of email traffic
• Forensic reports: Details of specific failures
• Identify unauthorized email sources
• Monitor legitimate third-party services