MX Lookup with SPF & DMARC Check
Check MX records, mail server IPs, SPF and DMARC for a domain
What an MX lookup tells you
MX (mail exchanger) records tell every sending mail server on the internet where to deliver email for a domain. Each record has a priority number and a hostname; senders try the lowest number first and fall back to higher ones if it's unreachable. If a domain's MX records are missing, wrong, or point at a host that doesn't resolve, mail bounces or silently queues — so checking MX records is the first step whenever email "isn't arriving", after a migration to Google Workspace or Microsoft 365, or before you cut over DNS to a new provider.
This MX lookup does more than list the records. It sorts mail servers by priority, resolves each mail server's A and AAAA records so you can see the actual IPs mail will be delivered to, and flags two special cases: no MX at all (senders then fall back to the domain's own A record under RFC 5321, which is rarely what you want) and a "null MX" (a single record of priority 0 pointing at ".", defined in RFC 7505, which means the domain deliberately accepts no email). You can also paste a full email address — the part after the @ is used.
The queries run on our server against the public resolver you choose — Cloudflare 1.1.1.1, Google 8.8.8.8 or Quad9 9.9.9.9. Nothing connects to the mail servers themselves and no email is sent, so this is a DNS-level check rather than an SMTP test. The domain you enter isn't stored.
A quick way to read the table: if your provider's setup guide lists specific MX hosts (for example Google Workspace's smtp.google.com, or a Microsoft 365 address ending in mail.protection.outlook.com), every row here should match it, and no leftover records from your previous host should remain.
SPF and DMARC checks alongside MX records
Getting mail delivered is only half the job; getting it accepted is the other. Receiving providers like Gmail and Outlook check two DNS records on every message, and since 2024 both Google and Yahoo require them for bulk senders. That's why this email MX record lookup also checks:
SPF — a TXT record on the domain beginning with v=spf1 that lists which servers may send mail for it, ending in a policy such as ~all or -all. The tool shows the record and warns if there is more than one, because multiple SPF records are a permanent error that makes SPF fail outright. Merge them into one record instead.
DMARC — a TXT record at _dmarc.yourdomain beginning with v=DMARC1. Its p= tag tells receivers what to do with mail that fails SPF and DKIM alignment: none (monitor only), quarantine (send to spam) or reject. A badge shows the policy; p=none is flagged amber because it protects nothing on its own — it's a starting point for gathering reports before tightening.
DKIM isn't checked automatically because its record lives at selector._domainkey.yourdomain and the selector varies by provider (google, selector1, s1…). If you know your selector, look it up as a TXT record with the DNS lookup tool. As an MX Toolbox alternative this page is intentionally narrow: fast, free, no account, and honest about checking from one location.
How to use the MX Lookup with SPF & DMARC Check tool
- 1
Enter a domain or email address
Type example.com or paste [email protected] — the domain part is used.
- 2
Choose a resolver
Cloudflare, Google or Quad9. Compare them if you've just changed records.
- 3
Read the mail server table
MX hosts are sorted by priority with their resolved IPv4 and IPv6 addresses.
- 4
Check SPF and DMARC badges
Green means present and sensible; amber flags multiple SPF records or a DMARC p=none policy; red means missing.
Frequently asked questions
What does MX priority mean?
Lower numbers are preferred. Senders try the lowest-priority MX first and only use higher numbers if it fails. Records with equal priority share the load.
Does this test whether the mail server accepts email?
No. It checks DNS only — MX, the servers' A/AAAA records, SPF and DMARC. It doesn't open an SMTP connection or send a test message.
Why is having two SPF records a problem?
RFC 7208 says a domain must publish at most one SPF record. With two, receivers return a permanent error and SPF fails. Combine the include: mechanisms into a single v=spf1 record.
Why isn't DKIM shown?
DKIM records sit under a provider-specific selector (for example google._domainkey.example.com), which can't be discovered from DNS. Look it up as a TXT record in the DNS lookup tool once you know the selector.
Is this a free MX Toolbox alternative?
Yes, for the common checks: MX records, mail server IPs, SPF and DMARC, with no signup. It queries from one server location and does not run blacklist or SMTP tests.
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