Gmail and Yahoo Sender Requirements: Readiness Guide
Large mailbox providers publish requirements for senders, especially higher-volume senders. Some requirements can be checked from DNS and SMTP, while others depend on message behavior, complaint rates and sending volume.
Authentication fundamentals
Sender readiness begins with correctly configured SPF or DKIM authentication and, for applicable bulk-sender requirements, DMARC.
Authentication should be evaluated together with alignment, because a technically valid authentication result does not necessarily mean that the visible From domain is aligned.
Forward and reverse DNS
Sending infrastructure should have coherent forward and reverse DNS. A sending IP can have a PTR hostname, and forward-confirmed reverse DNS checks whether that hostname resolves back to the original IP.
FreeMailCheck treats unavailable network evidence carefully rather than automatically declaring a sender noncompliant.
TLS and transport
SMTP TLS observations can help show whether transport encryption is available. Results can depend on the scanner network and remote server policy.
A failed outbound connection from one scanner is not by itself proof that the destination mail server is incorrectly configured.
Requirements DNS cannot prove
Complaint rates, actual daily sending volume, message formatting and operational unsubscribe processing cannot be conclusively determined from a domain's DNS records alone.
A readiness checker should mark such evidence as unknown unless message-level or sender-account data is available.
Free email diagnostics
FreeMailCheck provides free tools for SPF, DKIM, DMARC, DNS, SMTP, TLS, reverse DNS, email headers and sender compliance.
Browse all 61 tools →