MX Lookup
Articles, guides, and in-depth tips for the MX Lookup — everything you need to get the most out of it.
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What Your MX Records Reveal About Your Email Architecture — Provider Patterns, Redundancy Reality, and SMTP Queuing
MX Records Are Public Reconnaissance Data — Here's What Attackers Learn and How to Defend Against It
MX records are public reconnaissance data — attackers use them to identify email providers, target backup MX servers that have weaker filtering than primary MX, and exploit dangling MX records pointing to decommissioned servers. Here's the backup MX vulnerability, how null MX (RFC 7505) protects parked domains, the TTL preparation step for email migrations, and why using "mx" in SPF creates maintenance traps.
MX Records Tell You the Domain Works — Catch-All Configurations Are Why That's Not Enough
An MX lookup can show valid, correctly-configured mail servers — and "does [email protected] actually exist" still can't be answered, because MX records describe where mail for the domain goes, not which specific addresses are valid mailboxes. Here's how catch-all configurations make every local part "work" regardless of whether it's real, why this makes SMTP-based email verification inconclusive for catch-all domains, and why list-cleaning reports show an "unknown/risky" category for exactly this reason.
MX Record Priority and Failover: How Mail Servers Actually Choose Between Multiple MX Records
Multiple MX records don't load-balance by default — lower priority numbers are tried first, in strict order, with fallback only on connection failure (not on "recipient doesn't exist" responses). Here's how MX priority actually governs mail server selection, when equal priorities create real load distribution, the null MX convention for email-free domains, and practical MX configuration patterns.
Email Provider Migration: The Correct MX Record Sequence to Avoid Losing Email
Switching email providers is one of the most common causes of lost email. Here's the correct migration sequence (never update MX first), how Google Workspace, Microsoft 365, and Zoho Mail configure their MX records, and how to verify after migration.
MX Records and Email Delivery Failures: How to Diagnose and Fix Them
When email stops working, MX records are almost always part of the diagnosis. Here's how MX records control email delivery, how to debug bounces and delivery failures, common provider configurations, and the null MX for non-email domains.
MX Lookup — Check Any Domain's Mail Server Records Instantly
Learn how MX records work, what mail server priorities mean, how to read common configurations for Google Workspace and Microsoft 365, and how to use a free MX lookup tool to diagnose email routing.
