Email DNS Analyzer
MX, SPF, DMARC and — if you know the selector — DKIM. What each record says, what is wrong with it, and what a receiver will actually do.
Network request required This tool has to ask a DNS resolver, so the domain name you type is sent to it. Nothing else is: no cookies, no identifier, and nothing about you. Your browser makes the request directly — Toolsfully has no server involved and never sees the query. The resolver is yours to choose below, and each publishes its own privacy policy.
What each record does, and what this cannot tell you
MX says which servers accept mail for the domain. No MX means the domain receives no mail, which is correct for a website-only domain.
SPF lists which servers may send mail claiming to be from the domain. Its
hard limit is ten DNS lookups: past that, receivers stop evaluating and return a permanent
error, so the record fails rather than partially working. Each include costs one,
and each include's own includes cost more — which is why domains using several mail providers
quietly break.
DMARC ties the two together. It tells receivers what to do when SPF and
DKIM fail, and where to send reports. p=none blocks nothing at all; it is the
right place to start and the wrong place to stay.
DKIM signs messages so a receiver can verify they were not altered. Its
records live at <selector>._domainkey.<domain>.
Why the selector is required
There is no way to list a domain's DKIM selectors from DNS. A checker that reports on DKIM
without one is guessing at common names and reporting a guess that missed as a failure. This
tool asks for the selector instead — you will find it in the message headers of any mail the
domain has sent, in the s= field of the DKIM-Signature header.
What this does not do
It reads published DNS records. It does not send mail, does not test whether a message would be delivered, and cannot tell you about a receiver's own reputation filtering — which decides a great deal and is not visible from outside. Correct records are necessary and not sufficient.
Related tools
DNS Inspector for the rest of a domain's records. Subnet Calculator for the addressing.