Nine free tools for
email & DNS investigators.
Live answers from authoritative DNS. No signup, no quotas.
All 9 tools
Validate the person or company behind any email address.
Confirm if an inbox actually exists. SMTP-level check, no mail sent.
Inspect the mail servers that accept mail for any domain.
Check 50+ public RBLs for your domain or sending IP.
A · AAAA · CNAME · NS · TXT · MX records, live from authoritative DNS.
Discover the host, IP, location and infrastructure stack of any site.
Inspect SPF policy. Includes, mechanisms, the 10-DNS-lookup limit.
Verify policy, alignment and aggregate reporting setup.
Your public IP, geolocation, ISP and connection details.
Two reference databases to browse, not run.
The tools above answer a single question fast. The directories below are the long form: searchable catalogues of the registrars and networks our database tracks.
Domain Registrars
Every ICANN-accredited registrar we track, ranked by domain count. Profiles cover pricing, TLD coverage and abuse response.
Networks & ASNs
Autonomous system numbers, IPv4 and IPv6 prefixes, abuse contacts and rDNS hygiene. Trace any domain back to the network that hosts it.
From send to inbox, in five steps.
Every message runs through the same chain. Each tool checks a different link.
Domain & DNS
An email starts as a name. DNS records resolve that name to servers.
MX routing
MX records list the servers that accept mail for the domain, ordered by priority.
Authentication
SPF, DKIM and DMARC tell receivers the sender is allowed to send for the domain.
Reputation
Receivers check the sending IP and domain against public blocklists.
Inbox
If reputation holds, the recipient mailbox accepts and stores the message.
Each step has its own failure mode.
An SPF record won't help if the sending IP is on Spamhaus. A clean blocklist won't help if MX records point to an offline server. Each step needs to hold for mail to reach the inbox.
Use the tools above to isolate which step is failing, instead of guessing.
Three jobs, same five steps.
Marketers run these checks before campaigns to confirm authentication. IT teams use them to debug specific bounces. Security analysts use them to fingerprint phishing infrastructure.
The same DNS records that route legitimate mail also expose impersonation. Every result here is pulled live from authoritative DNS.
Common failure modes, and which tool finds them
Standard anti-spam behaviour. The retry succeeds. Don't page on it.
The sending IP appears on Spamhaus or similar. Receivers may reject or quarantine.
SPF goes to permerror once the includes resolve to 11+ DNS lookups. Flatten or trim.
Policy published but no rua= mailbox. Alignment failures stay invisible.