Gmail & Yahoo Bulk-Sender Readiness
Google and Yahoo enforce SPF + DKIM + DMARC alignment on bulk senders since 1 February 2024. Gmail's November 2025 escalation moved repeat offenders from tempfail to permanent rejection. Check your domain's posture in seconds.
Why this matters
In October 2023 Google and Yahoo jointly announced new requirements for any sender pushing 5,000 or more messages per day to their users. Enforcement began on 1 February 2024. For 21 months the failure mode was a temp-fail at SMTP — the message got deferred, the sender would notice, the admin would fix it.
That changed on 27 November 2025. Gmail moved repeat-offender bulk senders from tempfail to permanent rejection at SMTP. Yahoo followed in early 2026 with the same policy. If you are bulk-sending today without DMARC, SPF, and DKIM in alignment, you are not getting deferred — your messages are getting bounced. The complete requirements walk-through covers the underlying announcements and common-mistake pitfalls.
The bulk-sender requirements (Google + Yahoo)
| Control | Yahoo | |
|---|---|---|
| SPF aligned with From header | Required | Required |
| DKIM signed & aligned | Required | Required |
| DMARC at p=none or stricter | Required | Required |
| One-click unsubscribe (RFC 8058) | Required for marketing | Required for marketing |
| Inbound TLS on the SMTP connection | Required | Required |
| Spam complaint rate | < 0.3% | < 0.3% |
Volume threshold
The 5,000/day threshold is calculated per sending domain. Both providers count any sustained traffic above the threshold for a rolling 30-day window, so a single product launch that pushes you over puts the domain in scope for the next month. Treat the requirements as the baseline for every sending domain regardless of current volume — it is cheaper than firefighting on launch day.
What this tool covers
DNS-borne controls only: SPF, DMARC, MTA-STS, TLS-RPT, DNSSEC. DKIM cannot be verified from DNS alone — use the DKIM Checker with your specific selector to confirm the signing key. One-click unsubscribe lives in the message headers; use the Email Header Analyzer on a sample marketing send.
Diagnosing the actual rejection
Gmail and Yahoo each return distinctive bounce strings. Gmail typically says "Our system has detected that this message does not meet IPv6 sending guidelines regarding PTR records and authentication." Yahoo says "Message rejected for policy reasons [DMARC]." Both point at the same root cause as Outlook's 550 5.7.15: one of SPF or DKIM is producing an unaligned result and DMARC is therefore failing.
Outside this tool's scope
Spam complaint rate, IP reputation, and content scoring sit outside DNS posture. If your domain passes everything above and Gmail is still bouncing, work the Google Postmaster Tools dashboard (postmastertools.com) — it shows complaint rate, IP reputation, and authentication results for your domain across Gmail's user base.
Read the complete Gmail & Yahoo guide to learn more.
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