Free email DNS checker
Enter a domain, or an email address. See the MX records, the SPF record, and the DMARC record, each with a plain-English verdict. Add a DKIM selector only if you already know it.
Free, no signup. Every row comes from a DNS answer for the name you submit.
The lookup runs on the Uno Directory server and uses the DNS answers it gets back. It does not send mail, and the domain is not added to the directory.
Type a domain such as example.com, or an address such as you@example.com. The check uses the part after @.
Leave the DKIM selector empty unless you have one. It is the s= value on a DKIM-Signature header. The checker does not try common selector names.
Click Check DNS. Pass, warn, and fail describe that record only. A skipped DKIM row means no selector was entered.
Pass. The record is published, and this check did not see a missing policy, a second SPF or DMARC record, or +all.
Warn. Mail depends on an address-record fallback, SPF uses ?all or has no all mechanism, or DMARC is p=none (monitoring only).
Fail. The record is missing, the domain cannot receive mail, more than one SPF record is published, SPF uses +all, the top-level lookup count is over 10, or the DNS lookup itself failed.
Not checked. DKIM, when the selector box is empty.
How to read an email DNS check
MX records are how the rest of the internet finds a server that accepts mail for the domain. Each record has a priority and a host. The lowest number is tried first. If DNS returns no MX records, this page says the domain can't receive mail. When an A or AAAA address exists, some senders still try that address. The page lists those address records and calls that an implicit MX fallback. A null MX, the single record "0 .", is different: it tells senders not to deliver mail and not to try the address.
SPF is the TXT record that starts with v=spf1. It is the domain's list of hosts allowed to send mail as that domain. None means no such record was published. Two or more SPF records make the check unusable, because receivers are not supposed to pick one. +all means every host passes. ?all is neutral. Neither one stops an unauthorized server. The mechanisms include, a, mx, ptr, and exists, and the redirect modifier, each count as one DNS lookup, and SPF stops at 10. The number on this page is a top-level count of those terms on the record you publish. Included domains are not opened, so a record that looks under the limit here can still go over it at a receiver.
DMARC is a TXT record at _dmarc plus the domain. p= is the policy: none monitors, quarantine asks receivers to treat failing mail as suspicious, and reject asks them to refuse it. sp= is the policy for subdomains when it is set. pct= is how much of the mail the policy covers. rua= is where aggregate reports go. This page prints those tags only when they are in the record, and it says when a tag is absent. p=none is flagged because it does not ask anyone to quarantine or reject mail.
DKIM publishes a public key at a name you cannot discover from the domain alone: the selector, then ._domainkey, then the domain. Paste the selector if you have it. If you do not, the row stays unchecked. An empty p= value means that selector is revoked.
This check does not send a test message, and it does not connect to the mail hosts it finds. It cannot tell you that a specific message passed alignment. If you are cleaning a signup list instead of checking a domain's mail records, use the disposable email checker.
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