MX Record Lookup

Enter a domain to see which servers accept its email, in the order sending servers will try them. Each mail server is resolved to its IP addresses, and where the hostname identifies a known provider — Google Workspace, Microsoft 365, Titan, Zoho and others — that is named too.

The common misconfigurations are flagged: no MX records at all, MX records pointing at a CNAME, and hostnames that do not resolve.

How it works

MX (Mail Exchanger) records tell sending servers where to deliver mail for a domain. Each record has a hostname and a priority number, and lower numbers are tried first — a server at priority 10 is preferred over one at priority 20. Equal priorities share load between them.

Backup MX records at a higher priority used to be standard practice. They are far less useful now: a backup that simply queues mail and forwards it later often accumulates spam, and modern sending servers retry for days anyway. Most providers deliberately publish a single set of equal-priority records.

Three mistakes cause most mail routing problems:

• MX pointing at a CNAME. RFC 2181 forbids this, and some receiving servers refuse to deliver. The MX hostname must have an A or AAAA record directly.
• No MX records. Sending servers then fall back to the A record, so mail may reach your web server, which usually is not listening for it. Mail is silently lost.
• Leftover records from a previous provider. After a migration, an old MX left at a lower priority quietly captures mail that never reaches the new mailbox.

Changing MX records is subject to the same TTL caching as any DNS change. Lower the TTL a day before a mailbox migration, or sending servers will keep delivering to the old provider for as long as the old TTL allows.

Frequently asked questions