Domain Check
Test SPF, DKIM, DMARC and DNS for any domain. Free, instant, no ads.
Enter a domain and press Check.
All tools
My IP
Your public IP address, reverse DNS and the HTTP headers your browser sends.
Browser Info
Everything websites can read from your browser without asking: hardware, screen, network, locale.
DNS Lookup
Query any DNS record type for any domain: A, AAAA, MX, NS, TXT, CNAME, SOA, SRV, CAA.
SSL Checker
Inspect any site's TLS certificate: issuer, expiry date, alternative names and chain.
Subnet Calculator
CIDR and netmask math: network, broadcast, host range and usable host count.
Local Weather
Current conditions, forecast and sun times for wherever you are.
Games
Space Invaders and Arkanoid. For quality assurance purposes.
What this page does: it checks a domain's email authentication setup. SPF says which servers may send mail for the domain, DKIM cryptographically signs messages, and DMARC tells receiving servers what to do when those checks fail. This tool reads the actual DNS records, probes common DKIM selectors, and confirms basic DNS health (MX, NS, A, AAAA records). Useful before go-live, after mail migrations, or whenever mail lands in spam.