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Browse our complete collection of free DNS, email, and security tools. Everything you need to verify, troubleshoot, and secure your email infrastructure — no signup required.
Verify email addresses, check deliverability, and validate authentication records.
Check if an email address is valid and deliverable
Reveal mail server software and SMTP greeting banner for any domain
Parse and analyze raw email headers to trace routing and authentication
Analyze domain email configuration and get a heuristic spam risk score
Test if a mail server is an open relay that could be abused for spam
Scan all MX server IPs against 7 major DNS blacklists
Decode SMTP bounce codes and error messages with actionable solutions
Verify up to 20 email addresses at once. Check syntax, MX records, disposable domains, and risk score
Query DNS records, look up MX servers, check WHOIS data, and troubleshoot propagation.
Query all DNS records for any domain
Check if DNS changes have propagated across global servers
Find mail exchange servers for a domain
Get domain registration and ownership information
Check how old a domain is with registration, expiry, and registrar details
Find hostnames associated with any IP address via PTR records
Find the geographic location, ISP, and network info for any IP or domain
Calculate subnet details from CIDR notation or IP + subnet mask
Find authoritative nameservers for any domain
View all TXT DNS records including SPF, DKIM, and verification
Check Start of Authority records with serial, refresh, retry, and expire values
Look up IPv6 AAAA DNS records and check dual-stack support for any domain
Trace CNAME alias chains and resolve the canonical hostname for any domain
Find the Autonomous System Number, network operator, and ISP for any IP or domain
Check DNS records, SPF, and DMARC for up to 20 domains at once
Compare DNS records of two domains side by side
Take snapshots of DNS records and track changes over time
Check DMARC policies, validate SPF records, inspect SSL certificates, and audit domain security.
Comprehensive email & DNS security report with health score
Comprehensive security scan: SSL, headers, HTTPS redirects, and open ports
Check DMARC policy and configuration for a domain
Validate SPF records and email authentication setup
Flatten SPF records to direct IPs and reduce DNS lookups
Validate DKIM records and email signing configuration
Verify BIMI brand logo configuration and VMC certificate
Verify MTA-STS email TLS enforcement, policy file, and TLSRPT configuration
Verify DANE TLSA records for DNS-based certificate authentication
Check which Certificate Authorities can issue SSL certificates for a domain
Verify SSL/TLS certificate details and expiration
Check if your domain or IP is on email blacklists
Analyze HTTP response headers and security header configuration
Trace the full HTTP redirect chain for any URL with status codes and timing
Check open SMTP, IMAP, POP3, and web ports on any domain
Test which TLS protocol versions (1.0, 1.1, 1.2, 1.3) a server supports
Generate DMARC TXT records with policy, reporting, and alignment settings
Create SPF TXT records with authorized senders, IPs, and lookup validation
Generate DKIM TXT records with selector, key type, and hash algorithm settings
Detect CMS, frameworks, analytics, CDN, and server software on any website
Discover active DKIM selectors by scanning 30+ common selector names
Verify the complete SSL/TLS certificate chain with expiration and algorithm checks
Analyze HTTP security headers with A-F grading for HSTS, CSP, X-Frame-Options, and more
Verify DNSSEC configuration, DNSKEY and DS records, and chain of trust validation
Scan supported SSL/TLS cipher suites and test for weak ciphers and forward secrecy