Free email DNS tools

Free checkers for SPF, DKIM, DMARC and MX records. They run live DNS lookups and tell you what is wrong and how to fix it.

DKIM record checker
Free DKIM checker. Enter a domain and selector to fetch the public key record, follow CNAMEs, and flag revoked keys, weak 1024-bit keys and test mode.
DMARC record checker
Free DMARC checker. Reads the record at _dmarc.yourdomain, explains the policy (none, quarantine, reject), pct, report addresses and alignment, and flags common mistakes.
MX record checker
Free MX lookup. Lists a domain's mail exchangers in priority order, checks that each resolves to an IP, and flags CNAME targets, IP-address MX values and single points of failure.
SPF record checker
Free SPF checker. Looks up your domain's SPF record, counts DNS lookups against the limit of 10, and flags duplicate records, +all, ptr and broken includes.